Changing back a client to default image paths isn't hard at all and their are two methods to do this.
1.) Open the client in a hex editor (and know which items the "new" items replace and the IDs of the old items) find the new ID, replace it with the old ID.
2.) Rename the old items to the new items IDs, (BMPs,SMDs, everything) and then change the IDs server side in those items .inf files.