Click Exchange
 

How would one go about making one?

I managed to make part of one once, but I couldn't get the images to change due to the fact I asked the database to store an image they submitted.

If you want, I can show you what I had - which was the database submitting, pulling and displaying part. If you can just figure out a way to perhaps have the visitor submit a link and then pull the image from the page they submitted instead, it could work.

install a click exchange script. But if anything these would probably be frowned upon by adopt site owners? unless clicks required are very high.