The issue is described here:
https://community.plone.org/t/plone-app-multilingual-images-with-translatable-metadata-in-plone-5/2881
Basically, if an image field in a multilingual Dexterity content type is language-independent, all data managed for this image (by plone.app.imagecropping) should also be language-independent.
The issue is described here:
https://community.plone.org/t/plone-app-multilingual-images-with-translatable-metadata-in-plone-5/2881
Basically, if an image field in a multilingual Dexterity content type is language-independent, all data managed for this image (by plone.app.imagecropping) should also be language-independent.