What is the feature?
When cropping an image from the file picker, it would be much appreciated to be able to have at least some kind of visualisation of the new image’s dimensions / aspect-ratio
Even more appreciated would be to be able to lock users to some predefined aspect-ratio
What problem does this solve for you?
User cropping images in wrong aspect-ratios can cause problems in our front-end.
Informing users of what they are doing would be a first step.
Locking the tool to predefined aspect ratio (set in widget settings) would be 
Who else would be using this feature?
Every one using the file picker to upload images