I don't recall setting anything up to look at the pictures we put on a thumb drive.
A 'Home' screen which you will probably see when you select a 'Source', allows you to do a variety of things. I've only used it simply for looking at pics and listening to CD's.
I would say, if you get at least two USB, you should be covered.
I do believe the TV is becoming the central hub for a lot of your electronic activities.
Mine somehow displays caller ID when the phone rings. I'm stumped on that one. Cable is somehow connected to home phone in the TV.