One other important fact is that the larger images were on html pages and were clickable. I believe they get better conversion rates, but are harder to monitor for cheaters. There still seems to be a die hard group of TGP2 enthusiasts, and they state that their sites are more profitable than many TGPs.
Some attribute the lack of enthusiasm for TGP2 to the in-fighting and bickering that went on in the group. I made a couple of TGP2 galleries, but other than that, I haven't had much to do with the sites, so my post is really just hearsay.
