Some of the dragon-in-flight pictures are awesome! I didn't take so many as the "being a dragon" part of the game was not my favourite so it's interesting for me to see them.
Regarding the number of images, I can probably increase them but I'm slightly reluctant as it may have "unintended consequences" elsewhere, so they may just need to be split into separate replies. Other than that, I think the only real limitation is upload/download speeds,so it's best to make sure they're in jpeg format and scaled appropriately. I recently adjusted the forum width to scale to the window size so there isn't a definitive maximum but I'd stick to about 600-800px across and add a link if you think something is worth seeing full size, i.e.
I also need to remember to turn off the HUD when I'm doing screenies! Sometimes I do, often I don't.