One way would be including a button that searches a gif database like giphy so you don't have to manually go find it. It's more mobile user friendly than copy/pasting a link via the insert image button.
Kinda like what you have on discord on mobile, and what I have when texting (I have a Samsung idk if everyone has the same options) but it would make it a lot easier to find and post gifs, right now on mobile it's a process lol
I use the GIPHY app and can post gifs here on mobile (copy gif link instead of copy gif and imbed as an image, for anyone who wants to do the same), but having a solution imbedded on the boards would save a few clicks which is always appreciated.
Edit: I have the GIPHY app on iphone, apparently the Android one is different, so ymmv
To clarify, I open the gif in a new tab/browser window and copy the link to that tab (the gif source url). Then I paste that url into the image link button pop-up window that appears when I click on the button just to the right of the smiley face above the reply box.
Maybe that method could work for some other phones?