Use Difference Mode in Photoshop to Find…uh…Differences

I found a bug in Mudbox 2012 where 16-bit channel PNGs load as 8-bit but wanted to preserve the edits I’d done on this texture. So I copied the edited map to the 16-bit original and used difference mode to show where the changes were done and loaded that as a mask:

This is a good way of checking if two images that look similar are actually different.