Animated GIFs which are present in most of the apps have created a different atmosphere for emoji lovers. One can convey their message to the recipient easily just by a single tap. Emoji's being static, people started loving animated images which let them have fun with their friends.
An animated GIF is nothing but a graphic image created by combining a set of consecutive images. Though this Gif format was introduced in the late 1980s, it took a long time to appear in popular social media apps like Facebook. In December 2013, Facebook came up with video ads in the News Feed. But it did not receive good response thus allowing animated GIFs to enter this platform.
After supporting GIFs in News Feed and Status update, now they are testing on adding this format to comments well. Though this feature was not available before, people were commenting GIFs anyhow by using few browser extensions.
When TechCrunch enquired about it, Facebook had to say this, "Everyone loves a good GIF and we know that people want to be able to use them in comments. So we're about to start testing the ability to add GIFs to comments and we'll share more when we can, but for now we repeat that this is just a test."
Since they are into testing this feature now, it will be available only to a small percentage of users. Soon they may roll out to others as well if it gets a positive response. This feature is said to work similar to the GIF button present in the Facebook Messenger.