As of now this feature is only available on the web version of Facebook and should be rolling out to everyone across the world. The mobile apps can display images in comments but you can’t upload images as of now. Also, the website only supports still images and you can’t insert GIFs, which is unfortunate (or fortunate, depending upon your tolerance level for GIFs).
The ability to add images in comments is definitely a welcome feature and should be much more useful than recent additions such as hashtags to most of us.
Source: GSMArena
