IMO TGP (Thumbnail Gallery Post) and MGP (Movie Gallery Post) refers to the type of site. When it comes to free hosted galleries there are 2 kinds, picture galleries and movie galleries. Picture galleries usually contain 15-25 pictures. Movie Galleries (the ones that work best for me on my sites) contain 3-4 movies that are 10-15 secs long each. Thumb screen caps that are unclickable used to tease seem to work very well.

As far as what can be listed where, I list both movie and pic galls on all my tgp's like www.hugegaytgp.com and www.prostidudes.com but only list (or try to at least) movies galls on my mgp's like www.hotguysmovies.com and www.100gaymovies.com

Hope this helps. --Chubbs