See the update task here for inspiration for a go generate task:

https://github.com/Ranks/emojify.js/blob/master/gulpfile.js

The images´ license looks complicated:

https://github.com/arvida/emoji-cheat-sheet.com/blob/master/LICENSE

Not sure if there are any options here.

It could hook nicely into the transformer chain, maybe. Not sure how be should bundle the images.

Should have a flag, default off.