Accept batched tensor of images as input to image processor (#21144)

* Accept a batched tensor of images as input

* Add to all image processors

* Update oneformer

src/transformers/image_utils.py

@@ -91,6 +91,45 @@ def is_batched(img):
     return False
 
 
+def make_list_of_images(images, expected_ndims: int = 3) -> List[ImageInput]:
+    """
+    Ensure that the input is a list of images. If the input is a single image, it is converted to a list of length 1.
+    If the input is a batch of images, it is converted to a list of images.
+
+    Args:
+        images (`ImageInput`):
+            Image of images to turn into a list of images.
+        expected_ndims (`int`, *optional*, defaults to 3):
+            Expected number of dimensions for a single input image. If the input image has a different number of
+            dimensions, an error is raised.
+    """
+    if is_batched(images):
+        return images
+
+    # Either the input is a single image, in which case we create a list of length 1
+    if isinstance(images, PIL.Image.Image):
+        # PIL images are never batched
+        return [images]
+
+    if is_valid_image(images):
+        if images.ndim == expected_ndims + 1:
+            # Batch of images
+            images = [image for image in images]
+        elif images.ndim == expected_ndims:
+            # Single image
+            images = [images]
+        else:
+            raise ValueError(
+                f"Invalid image shape. Expected either {expected_ndims + 1} or {expected_ndims} dimensions, but got"
+                f" {images.ndim} dimensions."
+            )
+        return images
+    raise ValueError(
+        "Invalid image type. Expected either PIL.Image.Image, numpy.ndarray, torch.Tensor, tf.Tensor or "
+        f"jax.ndarray, but got {type(images)}."
+    )
+
+
 def to_numpy_array(img) -> np.ndarray:
     if not is_valid_image(img):
         raise ValueError(f"Invalid image type: {type(img)}")

src/transformers/models/beit/image_processing_beit.py

@@ -30,7 +30,7 @@ from ...image_utils import (
     ChannelDimension,
     ImageInput,
     PILImageResampling,
-    is_batched,
+    make_list_of_images,
     to_numpy_array,
     valid_images,
 )
@@ -438,9 +438,9 @@ class BeitImageProcessor(BaseImageProcessor):
         image_std = image_std if image_std is not None else self.image_std
         do_reduce_labels = do_reduce_labels if do_reduce_labels is not None else self.do_reduce_labels
 
-        if not is_batched(images):
+        images = make_list_of_images(images)
-            images = [images]
+        if segmentation_maps is not None:
-            segmentation_maps = [segmentation_maps] if segmentation_maps is not None else None
+            segmentation_maps = make_list_of_images(segmentation_maps, expected_ndims=2)
 
         if not valid_images(images):
             raise ValueError(

src/transformers/models/bit/image_processing_bit.py

@@ -30,7 +30,14 @@ from ...image_transforms import (
     resize,
     to_channel_dimension_format,
 )
-from ...image_utils import ChannelDimension, ImageInput, PILImageResampling, is_batched, to_numpy_array, valid_images
+from ...image_utils import (
+    ChannelDimension,
+    ImageInput,
+    PILImageResampling,
+    make_list_of_images,
+    to_numpy_array,
+    valid_images,
+)
 from ...utils import logging
 from ...utils.import_utils import is_vision_available
 
@@ -286,8 +293,7 @@ class BitImageProcessor(BaseImageProcessor):
         image_std = image_std if image_std is not None else self.image_std
         do_convert_rgb = do_convert_rgb if do_convert_rgb is not None else self.do_convert_rgb
 
-        if not is_batched(images):
+        images = make_list_of_images(images)
-            images = [images]
 
         if not valid_images(images):
             raise ValueError(

src/transformers/models/blip/image_processing_blip.py

@@ -29,7 +29,7 @@ from ...image_utils import (
     ChannelDimension,
     ImageInput,
     PILImageResampling,
-    is_batched,
+    make_list_of_images,
     to_numpy_array,
     valid_images,
 )
@@ -247,8 +247,7 @@ class BlipImageProcessor(BaseImageProcessor):
         size = size if size is not None else self.size
         size = get_size_dict(size, default_to_square=False)
 
-        if not is_batched(images):
+        images = make_list_of_images(images)
-            images = [images]
 
         if not valid_images(images):
             raise ValueError(

src/transformers/models/chinese_clip/image_processing_chinese_clip.py

@@ -30,7 +30,14 @@ from ...image_transforms import (
     resize,
     to_channel_dimension_format,
 )
-from ...image_utils import ChannelDimension, ImageInput, PILImageResampling, is_batched, to_numpy_array, valid_images
+from ...image_utils import (
+    ChannelDimension,
+    ImageInput,
+    PILImageResampling,
+    make_list_of_images,
+    to_numpy_array,
+    valid_images,
+)
 from ...utils import logging
 from ...utils.import_utils import is_vision_available
 
@@ -284,8 +291,7 @@ class ChineseCLIPImageProcessor(BaseImageProcessor):
         image_std = image_std if image_std is not None else self.image_std
         do_convert_rgb = do_convert_rgb if do_convert_rgb is not None else self.do_convert_rgb
 
-        if not is_batched(images):
+        images = make_list_of_images(images)
-            images = [images]
 
         if not valid_images(images):
             raise ValueError(

src/transformers/models/clip/image_processing_clip.py

@@ -30,7 +30,14 @@ from ...image_transforms import (
     resize,
     to_channel_dimension_format,
 )
-from ...image_utils import ChannelDimension, ImageInput, PILImageResampling, is_batched, to_numpy_array, valid_images
+from ...image_utils import (
+    ChannelDimension,
+    ImageInput,
+    PILImageResampling,
+    make_list_of_images,
+    to_numpy_array,
+    valid_images,
+)
 from ...utils import logging
 from ...utils.import_utils import is_vision_available
 
@@ -286,8 +293,7 @@ class CLIPImageProcessor(BaseImageProcessor):
         image_std = image_std if image_std is not None else self.image_std
         do_convert_rgb = do_convert_rgb if do_convert_rgb is not None else self.do_convert_rgb
 
-        if not is_batched(images):
+        images = make_list_of_images(images)
-            images = [images]
 
         if not valid_images(images):
             raise ValueError(

src/transformers/models/conditional_detr/image_processing_conditional_detr.py

@@ -44,7 +44,7 @@ from transformers.image_utils import (
     PILImageResampling,
     get_image_size,
     infer_channel_dimension_format,
-    is_batched,
+    make_list_of_images,
     to_numpy_array,
     valid_coco_detection_annotations,
     valid_coco_panoptic_annotations,
@@ -1172,9 +1172,9 @@ class ConditionalDetrImageProcessor(BaseImageProcessor):
         if do_normalize is not None and (image_mean is None or image_std is None):
             raise ValueError("Image mean and std must be specified if do_normalize is True.")
 
-        if not is_batched(images):
+        images = make_list_of_images(images)
-            images = [images]
+        if annotations is not None and isinstance(annotations[0], dict):
-            annotations = [annotations] if annotations is not None else None
+            annotations = [annotations]
 
         if annotations is not None and len(images) != len(annotations):
             raise ValueError(

src/transformers/models/convnext/image_processing_convnext.py

@@ -36,7 +36,7 @@ from ...image_utils import (
     ChannelDimension,
     ImageInput,
     PILImageResampling,
-    is_batched,
+    make_list_of_images,
     to_numpy_array,
     valid_images,
 )
@@ -272,8 +272,7 @@ class ConvNextImageProcessor(BaseImageProcessor):
         size = size if size is not None else self.size
         size = get_size_dict(size, default_to_square=False)
 
-        if not is_batched(images):
+        images = make_list_of_images(images)
-            images = [images]
 
         if not valid_images(images):
             raise ValueError(

src/transformers/models/deformable_detr/image_processing_deformable_detr.py

@@ -44,7 +44,7 @@ from transformers.image_utils import (
     PILImageResampling,
     get_image_size,
     infer_channel_dimension_format,
-    is_batched,
+    make_list_of_images,
     to_numpy_array,
     valid_coco_detection_annotations,
     valid_coco_panoptic_annotations,
@@ -1170,9 +1170,9 @@ class DeformableDetrImageProcessor(BaseImageProcessor):
         if do_normalize is not None and (image_mean is None or image_std is None):
             raise ValueError("Image mean and std must be specified if do_normalize is True.")
 
-        if not is_batched(images):
+        images = make_list_of_images(images)
-            images = [images]
+        if annotations is not None and isinstance(annotations[0], dict):
-            annotations = [annotations] if annotations is not None else None
+            annotations = [annotations]
 
         if annotations is not None and len(images) != len(annotations):
             raise ValueError(

src/transformers/models/deit/image_processing_deit.py

@@ -29,7 +29,7 @@ from ...image_utils import (
     ChannelDimension,
     ImageInput,
     PILImageResampling,
-    is_batched,
+    make_list_of_images,
     to_numpy_array,
     valid_images,
 )
@@ -276,8 +276,7 @@ class DeiTImageProcessor(BaseImageProcessor):
         crop_size = crop_size if crop_size is not None else self.crop_size
         crop_size = get_size_dict(crop_size, param_name="crop_size")
 
-        if not is_batched(images):
+        images = make_list_of_images(images)
-            images = [images]
 
         if not valid_images(images):
             raise ValueError(

src/transformers/models/detr/image_processing_detr.py

@@ -43,7 +43,7 @@ from transformers.image_utils import (
     PILImageResampling,
     get_image_size,
     infer_channel_dimension_format,
-    is_batched,
+    make_list_of_images,
     to_numpy_array,
     valid_coco_detection_annotations,
     valid_coco_panoptic_annotations,
@@ -1138,9 +1138,9 @@ class DetrImageProcessor(BaseImageProcessor):
         if do_normalize is not None and (image_mean is None or image_std is None):
             raise ValueError("Image mean and std must be specified if do_normalize is True.")
 
-        if not is_batched(images):
+        images = make_list_of_images(images)
-            images = [images]
+        if annotations is not None and isinstance(annotations[0], dict):
-            annotations = [annotations] if annotations is not None else None
+            annotations = [annotations]
 
         if annotations is not None and len(images) != len(annotations):
             raise ValueError(

src/transformers/models/donut/image_processing_donut.py

@@ -34,7 +34,7 @@ from ...image_utils import (
     ImageInput,
     PILImageResampling,
     get_image_size,
-    is_batched,
+    make_list_of_images,
     to_numpy_array,
     valid_images,
 )
@@ -396,8 +396,7 @@ class DonutImageProcessor(BaseImageProcessor):
         image_mean = image_mean if image_mean is not None else self.image_mean
         image_std = image_std if image_std is not None else self.image_std
 
-        if not is_batched(images):
+        images = make_list_of_images(images)
-            images = [images]
 
         if not valid_images(images):
             raise ValueError(

src/transformers/models/dpt/image_processing_dpt.py

@@ -31,9 +31,9 @@ from ...image_utils import (
     ImageInput,
     PILImageResampling,
     get_image_size,
-    is_batched,
     is_torch_available,
     is_torch_tensor,
+    make_list_of_images,
     to_numpy_array,
     valid_images,
 )
@@ -308,8 +308,7 @@ class DPTImageProcessor(BaseImageProcessor):
         image_mean = image_mean if image_mean is not None else self.image_mean
         image_std = image_std if image_std is not None else self.image_std
 
-        if not is_batched(images):
+        images = make_list_of_images(images)
-            images = [images]
 
         if not valid_images(images):
             raise ValueError(

src/transformers/models/flava/image_processing_flava.py

@@ -26,7 +26,14 @@ from transformers.utils.generic import TensorType
 
 from ...image_processing_utils import BaseImageProcessor, BatchFeature, get_size_dict
 from ...image_transforms import center_crop, normalize, rescale, resize, to_channel_dimension_format
-from ...image_utils import ChannelDimension, ImageInput, PILImageResampling, is_batched, to_numpy_array, valid_images
+from ...image_utils import (
+    ChannelDimension,
+    ImageInput,
+    PILImageResampling,
+    make_list_of_images,
+    to_numpy_array,
+    valid_images,
+)
 from ...utils import logging
 
 
@@ -647,8 +654,7 @@ class FlavaImageProcessor(BaseImageProcessor):
         codebook_image_mean = codebook_image_mean if codebook_image_mean is not None else self.codebook_image_mean
         codebook_image_std = codebook_image_std if codebook_image_std is not None else self.codebook_image_std
 
-        if not is_batched(images):
+        images = make_list_of_images(images)
-            images = [images]
 
         if not valid_images(images):
             raise ValueError(

src/transformers/models/glpn/image_processing_glpn.py

@@ -24,7 +24,7 @@ from transformers.utils.generic import TensorType
 
 from ...image_processing_utils import BaseImageProcessor, BatchFeature
 from ...image_transforms import rescale, resize, to_channel_dimension_format
-from ...image_utils import ChannelDimension, get_image_size, is_batched, to_numpy_array, valid_images
+from ...image_utils import ChannelDimension, get_image_size, make_list_of_images, to_numpy_array, valid_images
 from ...utils import logging
 
 
@@ -166,8 +166,7 @@ class GLPNImageProcessor(BaseImageProcessor):
         if do_resize and size_divisor is None:
             raise ValueError("size_divisor is required for resizing")
 
-        if not is_batched(images):
+        images = make_list_of_images(images)
-            images = [images]
 
         if not valid_images(images):
             raise ValueError("Invalid image(s)")

src/transformers/models/imagegpt/image_processing_imagegpt.py

@@ -23,7 +23,14 @@ from transformers.utils.generic import TensorType
 
 from ...image_processing_utils import BaseImageProcessor, BatchFeature, get_size_dict
 from ...image_transforms import rescale, resize, to_channel_dimension_format
-from ...image_utils import ChannelDimension, ImageInput, PILImageResampling, is_batched, to_numpy_array, valid_images
+from ...image_utils import (
+    ChannelDimension,
+    ImageInput,
+    PILImageResampling,
+    make_list_of_images,
+    to_numpy_array,
+    valid_images,
+)
 from ...utils import logging
 
 
@@ -196,8 +203,7 @@ class ImageGPTImageProcessor(BaseImageProcessor):
         do_color_quantize = do_color_quantize if do_color_quantize is not None else self.do_color_quantize
         clusters = clusters if clusters is not None else self.clusters
 
-        if not is_batched(images):
+        images = make_list_of_images(images)
-            images = [images]
 
         if not valid_images(images):
             raise ValueError(

src/transformers/models/layoutlmv2/image_processing_layoutlmv2.py

@@ -28,7 +28,7 @@ from ...image_utils import (
     ImageInput,
     PILImageResampling,
     infer_channel_dimension_format,
-    is_batched,
+    make_list_of_images,
     to_numpy_array,
     valid_images,
 )
@@ -230,8 +230,7 @@ class LayoutLMv2ImageProcessor(BaseImageProcessor):
         ocr_lang = ocr_lang if ocr_lang is not None else self.ocr_lang
         tesseract_config = tesseract_config if tesseract_config is not None else self.tesseract_config
 
-        if not is_batched(images):
+        images = make_list_of_images(images)
-            images = [images]
 
         if not valid_images(images):
             raise ValueError(

src/transformers/models/layoutlmv3/image_processing_layoutlmv3.py

@@ -30,7 +30,7 @@ from ...image_utils import (
     ImageInput,
     PILImageResampling,
     infer_channel_dimension_format,
-    is_batched,
+    make_list_of_images,
     to_numpy_array,
     valid_images,
 )
@@ -320,8 +320,7 @@ class LayoutLMv3ImageProcessor(BaseImageProcessor):
         ocr_lang = ocr_lang if ocr_lang is not None else self.ocr_lang
         tesseract_config = tesseract_config if tesseract_config is not None else self.tesseract_config
 
-        if not is_batched(images):
+        images = make_list_of_images(images)
-            images = [images]
 
         if not valid_images(images):
             raise ValueError(

src/transformers/models/levit/image_processing_levit.py

@@ -35,7 +35,7 @@ from ...image_utils import (
     ChannelDimension,
     ImageInput,
     PILImageResampling,
-    is_batched,
+    make_list_of_images,
     to_numpy_array,
     valid_images,
 )
@@ -303,8 +303,7 @@ class LevitImageProcessor(BaseImageProcessor):
         crop_size = crop_size if crop_size is not None else self.crop_size
         crop_size = get_size_dict(crop_size, param_name="crop_size")
 
-        if not is_batched(images):
+        images = make_list_of_images(images)
-            images = [images]
 
         if not valid_images(images):
             raise ValueError(

src/transformers/models/maskformer/image_processing_maskformer.py

@@ -37,7 +37,7 @@ from transformers.image_utils import (
     PILImageResampling,
     get_image_size,
     infer_channel_dimension_format,
-    is_batched,
+    make_list_of_images,
     valid_images,
 )
 from transformers.utils import (
@@ -717,9 +717,9 @@ class MaskFormerImageProcessor(BaseImageProcessor):
                 "torch.Tensor, tf.Tensor or jax.ndarray."
             )
 
-        if not is_batched(images):
+        images = make_list_of_images(images)
-            images = [images]
+        if segmentation_maps is not None:
-            segmentation_maps = [segmentation_maps] if segmentation_maps is not None else None
+            segmentation_maps = make_list_of_images(segmentation_maps, expected_ndims=2)
 
         if segmentation_maps is not None and len(images) != len(segmentation_maps):
             raise ValueError("Images and segmentation maps must have the same length.")

src/transformers/models/mobilenet_v1/image_processing_mobilenet_v1.py

@@ -35,7 +35,7 @@ from ...image_utils import (
     ChannelDimension,
     ImageInput,
     PILImageResampling,
-    is_batched,
+    make_list_of_images,
     to_numpy_array,
     valid_images,
 )
@@ -288,8 +288,7 @@ class MobileNetV1ImageProcessor(BaseImageProcessor):
         image_mean = image_mean if image_mean is not None else self.image_mean
         image_std = image_std if image_std is not None else self.image_std
 
-        if not is_batched(images):
+        images = make_list_of_images(images)
-            images = [images]
 
         if not valid_images(images):
             raise ValueError(

src/transformers/models/mobilenet_v2/image_processing_mobilenet_v2.py

@@ -36,7 +36,7 @@ from ...image_utils import (
     ChannelDimension,
     ImageInput,
     PILImageResampling,
-    is_batched,
+    make_list_of_images,
     to_numpy_array,
     valid_images,
 )
@@ -295,8 +295,7 @@ class MobileNetV2ImageProcessor(BaseImageProcessor):
         image_mean = image_mean if image_mean is not None else self.image_mean
         image_std = image_std if image_std is not None else self.image_std
 
-        if not is_batched(images):
+        images = make_list_of_images(images)
-            images = [images]
 
         if not valid_images(images):
             raise ValueError(

src/transformers/models/mobilevit/image_processing_mobilevit.py

@@ -28,7 +28,7 @@ from ...image_utils import (
     ImageInput,
     PILImageResampling,
     infer_channel_dimension_format,
-    is_batched,
+    make_list_of_images,
     to_numpy_array,
     valid_images,
 )
@@ -284,8 +284,7 @@ class MobileViTImageProcessor(BaseImageProcessor):
         crop_size = crop_size if crop_size is not None else self.crop_size
         crop_size = get_size_dict(crop_size, param_name="crop_size")
 
-        if not is_batched(images):
+        images = make_list_of_images(images)
-            images = [images]
 
         if not valid_images(images):
             raise ValueError(

src/transformers/models/oneformer/image_processing_oneformer.py

@@ -38,7 +38,7 @@ from transformers.image_utils import (
     PILImageResampling,
     get_image_size,
     infer_channel_dimension_format,
-    is_batched,
+    make_list_of_images,
     valid_images,
 )
 from transformers.utils import (
@@ -676,9 +676,9 @@ class OneFormerImageProcessor(BaseImageProcessor):
                 "torch.Tensor, tf.Tensor or jax.ndarray."
             )
 
-        if not is_batched(images):
+        images = make_list_of_images(images)
-            images = [images]
+        if segmentation_maps is not None:
-            segmentation_maps = [segmentation_maps] if segmentation_maps is not None else None
+            segmentation_maps = make_list_of_images(segmentation_maps, expected_ndims=2)
 
         if segmentation_maps is not None and len(images) != len(segmentation_maps):
             raise ValueError("Images and segmentation maps must have the same length.")

src/transformers/models/owlvit/image_processing_owlvit.py

@@ -29,7 +29,13 @@ from transformers.image_transforms import (
     to_channel_dimension_format,
     to_numpy_array,
 )
-from transformers.image_utils import ChannelDimension, ImageInput, PILImageResampling, is_batched, valid_images
+from transformers.image_utils import (
+    ChannelDimension,
+    ImageInput,
+    PILImageResampling,
+    make_list_of_images,
+    valid_images,
+)
 from transformers.utils import TensorType, is_torch_available, logging
 
 
@@ -300,8 +306,7 @@ class OwlViTImageProcessor(BaseImageProcessor):
         if do_normalize is not None and (image_mean is None or image_std is None):
             raise ValueError("Image mean and std must be specified if do_normalize is True.")
 
-        if not is_batched(images):
+        images = make_list_of_images(images)
-            images = [images]
 
         if not valid_images(images):
             raise ValueError(

src/transformers/models/perceiver/image_processing_perceiver.py

@@ -30,7 +30,7 @@ from ...image_utils import (
     ImageInput,
     PILImageResampling,
     get_image_size,
-    is_batched,
+    make_list_of_images,
     to_numpy_array,
     valid_images,
 )
@@ -289,8 +289,7 @@ class PerceiverImageProcessor(BaseImageProcessor):
         image_mean = image_mean if image_mean is not None else self.image_mean
         image_std = image_std if image_std is not None else self.image_std
 
-        if not is_batched(images):
+        images = make_list_of_images(images)
-            images = [images]
 
         if not valid_images(images):
             raise ValueError(

src/transformers/models/poolformer/image_processing_poolformer.py

@@ -36,7 +36,7 @@ from ...image_utils import (
     ChannelDimension,
     ImageInput,
     PILImageResampling,
-    is_batched,
+    make_list_of_images,
     to_numpy_array,
     valid_images,
 )
@@ -339,8 +339,7 @@ class PoolFormerImageProcessor(BaseImageProcessor):
         crop_size = crop_size if crop_size is not None else self.crop_size
         crop_size = get_size_dict(crop_size, param_name="crop_size")
 
-        if not is_batched(images):
+        images = make_list_of_images(images)
-            images = [images]
 
         if not valid_images(images):
             raise ValueError(

src/transformers/models/segformer/image_processing_segformer.py

@@ -30,7 +30,7 @@ from ...image_utils import (
     ChannelDimension,
     ImageInput,
     PILImageResampling,
-    is_batched,
+    make_list_of_images,
     to_numpy_array,
     valid_images,
 )
@@ -385,9 +385,9 @@ class SegformerImageProcessor(BaseImageProcessor):
         image_mean = image_mean if image_mean is not None else self.image_mean
         image_std = image_std if image_std is not None else self.image_std
 
-        if not is_batched(images):
+        images = make_list_of_images(images)
-            images = [images]
+        if segmentation_maps is not None:
-            segmentation_maps = [segmentation_maps] if segmentation_maps is not None else None
+            segmentation_maps = make_list_of_images(segmentation_maps, expected_ndims=2)
 
         if not valid_images(images):
             raise ValueError(

src/transformers/models/swin2sr/image_processing_swin2sr.py

@@ -22,7 +22,7 @@ from transformers.utils.generic import TensorType
 
 from ...image_processing_utils import BaseImageProcessor, BatchFeature
 from ...image_transforms import get_image_size, pad, rescale, to_channel_dimension_format
-from ...image_utils import ChannelDimension, ImageInput, is_batched, to_numpy_array, valid_images
+from ...image_utils import ChannelDimension, ImageInput, make_list_of_images, to_numpy_array, valid_images
 from ...utils import logging
 
 
@@ -148,8 +148,7 @@ class Swin2SRImageProcessor(BaseImageProcessor):
         do_pad = do_pad if do_pad is not None else self.do_pad
         pad_size = pad_size if pad_size is not None else self.pad_size
 
-        if not is_batched(images):
+        images = make_list_of_images(images)
-            images = [images]
 
         if not valid_images(images):
             raise ValueError(

src/transformers/models/vilt/image_processing_vilt.py

@@ -32,7 +32,7 @@ from ...image_utils import (
     PILImageResampling,
     get_image_size,
     infer_channel_dimension_format,
-    is_batched,
+    make_list_of_images,
     to_numpy_array,
     valid_images,
 )
@@ -441,8 +441,7 @@ class ViltImageProcessor(BaseImageProcessor):
         size = size if size is not None else self.size
         size = get_size_dict(size, default_to_square=False)
 
-        if not is_batched(images):
+        images = make_list_of_images(images)
-            images = [images]
 
         if not valid_images(images):
             raise ValueError(

src/transformers/models/vit/image_processing_vit.py

@@ -28,7 +28,7 @@ from ...image_utils import (
     ChannelDimension,
     ImageInput,
     PILImageResampling,
-    is_batched,
+    make_list_of_images,
     to_numpy_array,
     valid_images,
 )
@@ -243,8 +243,7 @@ class ViTImageProcessor(BaseImageProcessor):
         size = size if size is not None else self.size
         size_dict = get_size_dict(size)
 
-        if not is_batched(images):
+        images = make_list_of_images(images)
-            images = [images]
 
         if not valid_images(images):
             raise ValueError(

src/transformers/models/vit_hybrid/image_processing_vit_hybrid.py

@@ -30,7 +30,14 @@ from ...image_transforms import (
     resize,
     to_channel_dimension_format,
 )
-from ...image_utils import ChannelDimension, ImageInput, PILImageResampling, is_batched, to_numpy_array, valid_images
+from ...image_utils import (
+    ChannelDimension,
+    ImageInput,
+    PILImageResampling,
+    make_list_of_images,
+    to_numpy_array,
+    valid_images,
+)
 from ...utils import logging
 from ...utils.import_utils import is_vision_available
 
@@ -286,8 +293,7 @@ class ViTHybridImageProcessor(BaseImageProcessor):
         image_std = image_std if image_std is not None else self.image_std
         do_convert_rgb = do_convert_rgb if do_convert_rgb is not None else self.do_convert_rgb
 
-        if not is_batched(images):
+        images = make_list_of_images(images)
-            images = [images]
 
         if not valid_images(images):
             raise ValueError(

src/transformers/models/yolos/image_processing_yolos.py

@@ -42,7 +42,7 @@ from transformers.image_utils import (
     PILImageResampling,
     get_image_size,
     infer_channel_dimension_format,
-    is_batched,
+    make_list_of_images,
     to_numpy_array,
     valid_coco_detection_annotations,
     valid_coco_panoptic_annotations,
@@ -1038,9 +1038,9 @@ class YolosImageProcessor(BaseImageProcessor):
         if do_normalize is not None and (image_mean is None or image_std is None):
             raise ValueError("Image mean and std must be specified if do_normalize is True.")
 
-        if not is_batched(images):
+        images = make_list_of_images(images)
-            images = [images]
+        if annotations is not None and isinstance(annotations[0], dict):
-            annotations = [annotations] if annotations is not None else None
+            annotations = [annotations]
 
         if annotations is not None and len(images) != len(annotations):
             raise ValueError(

tests/utils/test_image_utils.py

@@ -20,7 +20,7 @@ import numpy as np
 import pytest
 
 from transformers import is_torch_available, is_vision_available
-from transformers.image_utils import ChannelDimension, get_channel_dimension_axis
+from transformers.image_utils import ChannelDimension, get_channel_dimension_axis, make_list_of_images
 from transformers.testing_utils import require_torch, require_vision
 
 
@@ -102,6 +102,58 @@ class ImageFeatureExtractionTester(unittest.TestCase):
         self.assertEqual(array5.shape, (3, 16, 32))
         self.assertTrue(np.array_equal(array5, array1))
 
+    def test_make_list_of_images_numpy(self):
+        # Test a single image is converted to a list of 1 image
+        images = np.random.randint(0, 256, (16, 32, 3))
+        images_list = make_list_of_images(images)
+        self.assertEqual(len(images_list), 1)
+        self.assertTrue(np.array_equal(images_list[0], images))
+        self.assertIsInstance(images_list, list)
+
+        # Test a batch of images is converted to a list of images
+        images = np.random.randint(0, 256, (4, 16, 32, 3))
+        images_list = make_list_of_images(images)
+        self.assertEqual(len(images_list), 4)
+        self.assertTrue(np.array_equal(images_list[0], images[0]))
+        self.assertIsInstance(images_list, list)
+
+        # Test a list of images is not modified
+        images = [np.random.randint(0, 256, (16, 32, 3)) for _ in range(4)]
+        images_list = make_list_of_images(images)
+        self.assertEqual(len(images_list), 4)
+        self.assertTrue(np.array_equal(images_list[0], images[0]))
+        self.assertIsInstance(images_list, list)
+
+        # Test batched masks with no channel dimension are converted to a list of masks
+        masks = np.random.randint(0, 2, (4, 16, 32))
+        masks_list = make_list_of_images(masks, expected_ndims=2)
+        self.assertEqual(len(masks_list), 4)
+        self.assertTrue(np.array_equal(masks_list[0], masks[0]))
+        self.assertIsInstance(masks_list, list)
+
+    @require_torch
+    def test_make_list_of_images_torch(self):
+        # Test a single image is converted to a list of 1 image
+        images = torch.randint(0, 256, (16, 32, 3))
+        images_list = make_list_of_images(images)
+        self.assertEqual(len(images_list), 1)
+        self.assertTrue(np.array_equal(images_list[0], images))
+        self.assertIsInstance(images_list, list)
+
+        # Test a batch of images is converted to a list of images
+        images = torch.randint(0, 256, (4, 16, 32, 3))
+        images_list = make_list_of_images(images)
+        self.assertEqual(len(images_list), 4)
+        self.assertTrue(np.array_equal(images_list[0], images[0]))
+        self.assertIsInstance(images_list, list)
+
+        # Test a list of images is left unchanged
+        images = [torch.randint(0, 256, (16, 32, 3)) for _ in range(4)]
+        images_list = make_list_of_images(images)
+        self.assertEqual(len(images_list), 4)
+        self.assertTrue(np.array_equal(images_list[0], images[0]))
+        self.assertIsInstance(images_list, list)
+
     @require_torch
     def test_conversion_torch_to_array(self):
         feature_extractor = ImageFeatureExtractionMixin()