I took some pictures, mostly from the outside though, because it's hard to get in and not bother students or people on a meeting... I also don't know if it's okay to take pictures of certain places (I hope my pics are okay by the way) but this should be enough for you to have an idea if you are curious. :)
Gnomon is inside Hollywood's Television Center so it might be a little bit hard to find it unless you know how does it look like. There's no signs saying that Gnomon is there, so if you ask someone they probably won't even know and be able to give you directions. I know people living around for years and they never knew about the school.
But when you get inside, you find yourself inside a maze of corridors and stairs, you won't really know what part of the building is part of Gnomon or not, although you will probably get used to this after some time.... (but I, for example, still get lost inside this place sometimes hahaha). But anyway, these are the places I frequent the most.
If you see this from the outside, you are in the right place:
After the entrance, to the right. The first thing you'll find are the reception, which is near Brian's and Shannon's office at the first door right below the "G" sign and the second door will be the Gnomon Store. The next thing you'll see are the stairs for the second floor (where the figure painting and figure drawing classes are) together with the Patio and the Gnomon Lounge if you want to have a snack :) :
Then, a little bit ahead will be a little corridor on your left, where you can park your bicycle in case you are using one. After this you can turn to the next right and ahead, OR if you didn't turn to the left where the bicycles are but go ahead and then turn to the next left, you'll end up in the same place, where Pixologic, the Gnomon Gallery and the sculpting classroom are. And there's also another place to relax :)