After you check that out, we mentioned on that page that there are lots of places to host GIFs.
Here is our Padlet example. A teacher can create a Padlet page and then only needs to provide students with the link. Students don't need an actual account. By just double clicking, they can make a post and comment on a GIF. They can also post their own. Padlet also allows you to turn on "approval only" so that posts only show if you approve them. We have our Padlet commenting turned off right now.
Here is our Linoit example. The navigation menu is in the bottom right. If you drag that white rectangle around, you can see where we have posted some of our GIFs with questions. We have commenting turned off, but if turned on in the settings, it allows students to answer questions about GIFs on different colored sticky notes. Students don't need an actual Linoit account---they just need the link provided by their teacher!