It creates another pic/file in your uploads.

If it worked like you prefer, here is what could happen  ( for example):

You have pic_1 in cat_1
You copy pic_1 to cat_2
Now if you decide you no longer need the pic in cat_1 and delete it, there will be no pic to display in cat_2

Well I guess I just answered my own question by installing it then checking the URL of copied pics.

This makes a duplicate of the actual file.

While this is a sweet mod and I give props to Artie (and Gorgon) for putting it together, the only way this could get any sweeter is as I described before. To make a pic tied to multiple categories within the db, which would allow you to save disk space by not having duplicated files, but rather still appearing in multiple categories. I supposed that would be bordering on the requested "tags" mod.

Still very useful though and I appreciate it! Thanks guys!

It should be  possible to make it work as you want by removing the code that renames the file.