Fascinating. It is definitely not "fine", it's a significant security flaw. Users may have removed parts of an image that are confidential/would pose all kinds of risks if seen, and they are entitled to think that cropping would never allow recovering the original image.
From a developer's POV, both the ability of recovering the original image and the resulting size would normally be immediate concerns.
Sure for the first one, actually, exploit or not, it may even have been thought of as a "feature".
And who cares about the end result (security, file size), both were probably not mentioned in the "user stories" that were the basis for developing this tool.
