now about TGPs what you have to know is that there are real TGPs and fake TGPs. real ones have a submit feature where other webmasters submit their galleries and those kind of TGPs can get huge traffic but there is a lot of work to do with the maintenance of the script, galleries approval, problems with cheaters and so on. fake ones are easy to install and maintain, you just setup the script and load it with FHGs from your sponsors and all you have to do is get traffic... but this kind of TGPs dont get massive traffic because you have the same reused FHGs that are on 100s of other sites and surfers want fresh content...
anyway don't expect to make a killing with TGPs cause the general surfer base is made of freeloaders looking for something to jerk off, not to spend money... if you want to make some cash with this build a network of about 30 TGPs, get some
PR and traffic and then sell links and partner accounts.... i think you'll make more money with blogs not TGPs but it is you call...
about the scripts, for real ones use Comus Thumbs or Smart Thumbs, those are paid scripts but they have a free edition with a 1.5-2% skim and for a fake TGP you can use zippedtgp.