Customizing Export Options for Images
If an epub is exported with the “Use Existing Image for Graphic Object” option selected, crop information is not maintained on any of the exported images. If you select "Preserve Appearance from Layout", the crop is maintained, but the images are downsampled quite extensively.
There should be a way to export the images in their original resolution while also preserving the crop information, or at least having more customizable image export settings.
Metin shared this idea