Command-a-vision fix

[dongluw]

What does this PR do?

• fix a bug in the image resize code, which affects performance
  before fix:

after fix:

• add test cases

Fixes # (issue)

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[Rocketknight1]

cc @molbap @yonigozlan @zucchini-nlp

[molbap]

Hi @dongluw , thanks for the contribution, indeed there seems to be a flip issue. however how do you obtain the test image above? I'm surprised our tests haven't caught this, it should be all wrong, so a reproducer would help

[github-actions]

[For maintainers] Suggested jobs to run (before merge)

run-slow: cohere2_vision

[dongluw]

hey @molbap I saved the stacked_images to images patch by patch https://github.com/dongluw/transformers/blob/9ef13ef775fe5a05c634fb2705a500ef59f28763/src/transformers/models/cohere2_vision/image_processing_cohere2_vision_fast.py#L228

this issue only affects generation quality if images are of very high/low aspect ratio

full image is