How 2 add a preview to a gif in ur stash:
1. Go to the gif in your stash and press "Submit to DeviantART"
2. Then you can add a preview in the submission options
3. If it's larger than 150x150 the preview won't be animated but you can make a smaller version of your gif that is that size with various sites! I use this one: ezgif.com/resize
(make sure you keep aspect ratio so it dun squish ur gif)
4. It saves it in stash so you can close out of your submission tab