Reaction GIFs are already a common sight on Tumblr, but this new feature might make them even more prolific. The social network/blogging platform now has a built-in GIF search and insert feature: simply click the plus sign (+) while you're creating a post, click GIF and type in any term you want, such as "slow clap" to get the one above. When the animated images show up, just choose one, and it will be embedded into your post with the proper credits. On the other hand, you'll get a notification if other people use your images, which only means you can contribute by uploading your own. So, make sure to post GIFs from your extensive collection first, before completely nuking them -- if you can stomach deleting years of hard work, that is -- from your computer.