The USB port on your TV is so that you can put a USB flash drive into the TV.
From that USB flash drive you can view pictures and videos you have stored on the USB flash drive.
I will store pictures on flash drives and then I have a small LED TV in my office on the wall that I will play a slideshow of pictures on through the USB flash drive.
So you could put photos on a USB drive and then insert it into the TV USB port and display pictures on your TV if you want too.
You can also have videos on that USB drive to play on the TV as well.