My free site (similar to TGPs) has the galleries lead to pics that are on HTML pages.
http://www.sleazydream.com/main.html
I find the clickthrough isn't nearly as good as the gallery itself, and the galleries arn't even close to what the main page does. With the same traffic on each??? Weird. But enough to warrent doing it. Actually I mostly do it to increase the total clicks I send to my pre-paid sponsers.
I think the reason most tgps dont' take submissions with HTML pages is that people tend to go overboard with ads more often than not.