I've downloaded a couple of files ending with .img such as *****, *****, ***** on a Mac but none of them can't be mounted by DiskCopy 6.3. First DiskCopy said about wrong file type. This is easy fix. Then it said unexpected end-of-file reached.

This is impossible that every files was screwed. Does anybody have similar experience ?

What I do is this: I drop the img file in my Stuffit Expander icon on my desktop and automatically mounts the disk img on my Desktop.
Good luck