We just returned from Yellowstone. The Park has never been more crowded. According to a Ranger we spoke to he said that attendance this year is up 50% over last year which was up 30% over the year before. So Be prepared to wait. Some parking lots were to full to hold everyone. They even parked out on the roads entering the parking lots. I suggest going very early in the morning to those things you want to see first. By 9:30 - 10:00 AM the lots are full. If you are going to be there after school starts for most kids you may not find it a problem. You may still compete with the foreign visitors. There were a lot of them. We camped at Bridge Bay. It is central to the 2 loops around the park. It's a big place so be prepared to put on a lot of miles both on your car and your feet.
Just a warning. The new park fees went up this year. It costs 30 dollars to enter both the Tetons and Yellowstone. You can buy a combo pass for both parks for 50.00. If you are only interested in Yellowstone do not come in from the south entrance if you don't want to pay the extra 25.00 for the Tetons. They have basically made the road in from the south a toll road.
We stayed in Gros Venture in the Tetons. If you pass through the Tetons and are looking for an interesting place for photos you might check this place out. Just north of the entrance to the Gros Venture CG is a gravel road called Mormon Row. It goes for about 2-3 miles. Lots of wild life, Bison, Pronghorn and Mountain Bluebirds. I just happened to talk to the guy that cleans the restrooms and he told me about it. There are 2 areas with old barns and buildings. Early mornings have the best light.
This is one of the barns. It is said to be the most photographed barn in WY.