Yes. When we add new emoji here, they are automatically added to the pop-up menu accessed from the colon. When you hit a colon, click the “more…” at the bottom of the popup list, then go to the last tab (a )
The problem with the emojis above is that when I add them to Discourse, they are automatically squeezed into a 50x50 pixel square (maybe it isn’t 50, but it is definitely square), so they become distorted. I have tried making them into square images, but then they get shrunk when positioned in Discourse’s emoji library.
For my reference - these images below reside on our old phpBB website