I noticed this the other day. On auctions where you can zoom in on the pictures, the file name ends with "32" and on auctions where the seller didn't allow zooming, the file name ends with "12" or some other number. Well, over half of the time you can change the "12" or whatever other number might be there to "32" and view a much larger image if the seller actually uploaded a large image to begin with.
For example... this auction had one of those disappointing "12" images that eb@y won't let you zoom in on. It's pathetic to look at these and even more pathetic to save to your computer for reference.