Disney’s California Grill restaurant at the Contemporary Resort has an outdoor walkway which provides great views of Magic Kingdom and other parts of Walt Disney World property. Although the sun was a little blinding while we ate until they lowered the blinds in the restaurant, we did enjoy seeing the sunset behind the Castle. You can also see the Magic Kingdom fireworks from this restaurant, but I have not done that yet. I enjoy watching them in the park.
The top of the Family Raft Ride at Blizzard Beach water park also provides nice panoramic views of the surrounding parks, however, you have to climb up about a hundred steps. And, you don’t have much time to take a photo before you have to get on the ride. If you go for Early Extra Magic Hours most people go to the larger rides and so the Family Raft Ride has no crowd. If you have a waterproof case for your phone or camera, you might be able to take photos before the raft ride but otherwise it would be hard to bring a phone or camera up there.
As you are climbing the hill on Expedition Everest, you can see the Tree of Life on one side and on the other side can see a few other parks. I was able to quickly snap a photo of the Tree of Life but did not have time to get any photos of the other side, so I will have to try again next time. Everest is the highest mountain in Walt Disney World and therefore your best chance of getting a good photo of a lot of WDW property is from this roller coaster ride. But enjoy the view especially if it is your first time riding, before trying to take a photo.
When the doors open when you are dropping on the Tower of Terror, you can see the Mouse Ear Tower, but the doors shut too quickly as you drop to be able to get a picture. I would recommend just enjoying the ride because it is hard enough to stay in your seat, nevertheless attempt to take a photo!
The easiest, non moving spot to see a large part of Magic Kingdom from and take photos is the California Grill restaurant, but if you want to see another park from a high vantage point, then you might have to try one of the other options above.