Indeed, additional programming could be done but I doubt this website has the resources/manpower to do all that right now (it would take months).

A better solution (for now) would be for moderators to put all similar art into one big new "upload" and then re-calculate the medals for that user. Or heck, just do it from now on. Perhaps make a rule that uploading individual art assets is forbidden?

Or, to make a more radical change like ceninan said, award medals based on user feedback. Put a five-star rating next to each project. That removes all the hassle, provides a fair medal system (your quality artwork that took months no longer earns the same medals as my mspaint pixel guy) and leaves only one problem: the database that is currently full of stuff like:

Hard Vacuum: GrssMisc
Hard Vacuum: GrssCrtr
Hard Vacuum: Grss2Lav
Hard Vacuum: Grs2Watr
Hard Vacuum: Grs2Mnt   
Hard Vacuum: Grs2Crtr
Hard Vacuum: Grs2Crtc   
Hard Vacuum: Grs2CrtB

Instead of simply making one asset called "Hard Vacuum" :)