The URL in your quota is the same no matter what, so if you can drag them all out individually, shift Z them, then right click and get their URL's. Then you can make a journal entry handout displaying each one and place an api button on them that sets them as their default tokens image and updates the token. Tokenmod would be required for sure, possibly one of the handout api's also. I do something similar to this with my random npc generator so my only word of advice prep wise is that it is very tedious the larger the token image pool is. God help me if they ever change the URL's of my images on their site.