David, I think you are wrong if I understand your post correctly, when you say, "You can only use a representative chip scan if you own or owned the chip in that scan. " Often I get a box of 100 poker chips, all in the same condition -- let's say very fine condition. If I put them on eBay one-at-a-time, I don't think it is necessary to take a scan of each individual chip as I post it. Hardly anyone would care. And I think all sellers would do the same. If you have 100 of a chip and put a picture on your web site, I am sure you don't change the picture after each sale.
Robert