In our humble opinion, pictures are the BEST souvenirs you can get. Why is that? They have you and your family in it, they are help capture the memory, they’re fun, and best of all they’re CHEAP!
However, pictures at Disney can be expensive. Disney's PhotoPass for our family was just a little too pricey. Also, we didn’t see a lot of Disney PhotoPass photographers in the parks. Besides, it really is just cheaper to have a random person snap your picture.
Souvenir article for more ideas.
Alternatively, nothing stops you from taking a picture of your picture on screen. We did this for the pictures after Rockin' Roller Coaster, Expedition Everest, and Tower of Terror. Sure, they may be a bit grainy, but they still capture the fun! If you are worried about upsetting the Disney people, never fear. There are typically Disney Cast Members around the screens flashing after-ride pictures. Not one of the workers said anything to us.