It's easy to hop online and find information on just about anything, but it's also easy to find unreliable, downright wrong information, too. Google Images can help detect a fake news story written around an image.
As CNET points out, there are some fairly obvious guidelines for weeding out a lot of fake news stories, but Google Images makes it easy to see where an image originates. Just take a screenshot, drag it into Google Images, then search for the original source. Chances are, you'll see sources that have already found the image to be miscaptioned or just fake. For example, CNET's Laura Hautala says she used this on a photo of Susan B. Anthony that recently went viral. Turns out, it wasn't Susan B. Anthony. (If you search the image, you can find the original source here, the front page of the Daily Mirror newspaper in 1910.)
Of course, Google Images will simply show you other places the photo is found online, so it's up to you to read those sources and search for the original to see what the actual source says about the photo. Still, it's a good place to start and an easy enough tip to follow.