Step #1: Click the white space in the comment box or reply button first in order for the "Add Media" to show up.
Excited waving wave cheer yay for you eager
Got permission to expand them and easy accessible, follow the site to support more of these~
( ´ ▽ ` )ﾉ Credits:
Here's the account on dA:
If you are at the movile app, I don't really know how, but if you are at a PC, do this:
Click to make a comment, underneath there will be either a plus sign or a thing that shows you a picture, two pictures, a video a smiley face and the word GIF, click on either of the choices, if you have a plus sign, click it and you will see it, or for movile app you can make a similey face and it will become a gif emoji thingy