You can also go here for higher res screenshots. Sadly, these aren't in 1280x720 either. I wonder why they aren't, the game is definitely going to run at that resolution on the PS3. Maybe these are screenshots from the PSV version.
-edit-
I also think some of you guys are forgetting how the game actually looked on the PS2. Here are some screenshots I made with an emulator running at the PS2's native resolution, with a window size at roughly 1280x720. I didn't care to measure it precisely, so I just eyeballed it. Maybe after looking at these, you'll more easily notice how much better the game looks now than what it did on PS2.
Nevermind Yuna's third arm. That's just a deinterlacing artifact that shows up when you take still images. It's not very noticable when you're actually playing.