VLMs: patch_size -> num_image_tokens in processing (#33424)

* use num additional tokens

* fix copies + docs

* another fix copies :)

* add docs

* move order for BC

docs/source/en/model_doc/blip-2.md

@@ -40,6 +40,10 @@ The original code can be found [here](https://github.com/salesforce/LAVIS/tree/5
 - BLIP-2 can be used for conditional text generation given an image and an optional text prompt. At inference time, it's recommended to use the [`generate`] method.
 - One can use [`Blip2Processor`] to prepare images for the model, and decode the predicted tokens ID's back to text.
 
+> [!NOTE]
+> BLIP models after release v4.46 will raise warnings about adding `processor.num_query_tokens = {{num_query_tokens}}` and expand model embeddings layer to add special `<image>` token. It is strongly recommended to add the attributes to the processor if you own the model checkpoint, or open a PR if it is not owned by you. Adding these attributes means that BLIP will add the number of query tokens required per image and expand the text with as many `<image>` placeholders as there will be query tokens. Usually it is around 500 tokens per image, so make sure that the text is not truncated as otherwise there wil be failure when merging the embeddings.
+The attributes can be obtained from model config, as `model.config.num_query_tokens` and model embeddings expansion can be done by following [this link](https://gist.github.com/zucchini-nlp/e9f20b054fa322f84ac9311d9ab67042).
+
 ## Resources
 
 A list of official Hugging Face and community (indicated by 🌎) resources to help you get started with BLIP-2.