Wrist Pics is an app which allows you to browse images posted in subreddits on reddit.com.
The app on your phone lets you edit the list of subreddits that will be available to view on your watch.
On your watch, you simply need to tap on the currently displayed image in order to go to the next image.
If you do a long press on your watch, you will be able to select another subreddit to browse the images on.
Many images have descriptions included with them. You can either use your finger to scroll the screen downward in order to see the description, or use the digital crown to scroll instead.
Please note that subreddits are public forums, and while moderated, some may contain images that may be offensive to some people. Please keep this in mind as you are using this app.