Here's what you should and shouldn't plug into a TV USB port

Turn the TV into a picture frame

You don't need a TV that doubles as a picture frame in order to display some art in the home. You can simply load up some images onto a USB stick, plug it in and let the TV do the rest. It should automatically recognize the images and give an option to view them as a slideshow. Most TVs will also let you loop a single image continuously.

You could run into issues regarding file types, just as with video footage. To be safe, stick with common file types like JPEG and PNG.

That said, not all TVs are well-suited to this kind of usage — in fact, most aren't. There's a reason Samsung's Frame TVs are specifically designed to run in always-on mode. Regular TVs will use a lot of power to show some artwork, and some models of OLED sets are susceptible to burn-in. So, even if you do give this a shot, shut things down when you're not in the room and make sure the images cycle consistently so one shot doesn't end up there forever.

Charge up gadgets (but be prepared to wait a while)

This is a good news/bad news type of situation. You can use a TV's USB port to charge up a phone, tablet or a similar gadget in a pinch, but it will likely take a long time. That's because most modern smart TVs ship with USB 2.0 ports, which offer a modest 5V at 500mA. This would take around seven hours to charge up a newer phone. A laptop could take around 20 hours to top off. That's simply not practical.

However, there is a spot of good news. The industry has slowly been moving toward USB 3.0, with many newer TVs offering the feature. This will speed things up. In any event, even USB 2.0 ports are great for charging low-power devices like mobile accessories.

Some USB-powered devices won't work

Not all USB-powered devices will work with smart TVs. This is particularly true of devices that require some kind of software driver to work. This includes stuff like USB printers, optical drives and scanners. The TV won't recognize them when connected.

There are some workarounds, but they can be finicky. Some optical disc drives are designed with TV connections in mind, but they only work with certain models. Some Android TVs can accept sideloaded apps that accept printer connections, but the process can be cumbersome.