Elise:
I hope this tutorial will let you post GIFS :)
1. Go to Giphy, Tumblr, or Tenor and click on the the gif you want to use
2. Right click on the gif and click Open Image in New Tab (If you're on the phone, tap and hold on the gif until it gives you the option to open the image in a new tab).
3. Copy the link address from that new tab you just opened.
4. On MDL, hover over the Insert Image option and paste the link address.
5. Click the Insert button and you should have the GIF added to your reply :)
Here, Wanning94. This tutorial is from our Queen of Gifs, Elise.
Posting images is pretty much the same thing.
BTW, she hasn't been here in ages. Elise, where are you???