Sometimes one image isn’t enough to illustrate an entire pro or con. In order to show how an app has light and dark skins available, it would be best to add an image of each one to show both. Users could then scroll through the pictures in the same way as the sources.
Another example could be custom android watch faces where a pro on Planets mentions that there are two themes to choose from. If two pictures could be uploaded, users could see both themes instead of just one.