How to reproduce: - Have image editor and GPU compositor backdrop enabled and showing the same image - In image editor, apply operator flip horizontally - Notice how image editor gets updated but compositor backdrop doesn't Fixes backdrop for GPU compositor for the following operations: - image -> transform -> Flip horizontally - image -> transform -> Flip vertically - image -> transform -> Rotate 90° clockwise - image -> transform -> Rotate 90° counter-clockwise - image -> transform -> Rotate 180° Pull Request: https://projects.blender.org/blender/blender/pulls/119819