Image Transforms should reflect the policy of the parent image.

Steps to reproduce:

1. Drop a Pikachu image (image A) on a Task description and save (now it's attached to that Task)
2. Visit the Pikachu image and click on "Generate transforms" and share one random generated transform (image B) to somebody else

→ That person can see image A, but cannot see Image B

Why this is needed:

This missing feature is needed by D25475: Drag & Drop Task Cover Image: also attach since it attach the image, but its card transform is still invisible to other people.