But most chats like discord / signal / telegram / fb messenger(?) can already react to images you send. Just send them in your group chat, then upload the ones with the most reaction.

Its almost there. The difference is the tinder like UX of swiping to input approval data, and being able to programmatically export the approval data so other apps can use it without you having to do it manually

Its not impossible that those chat platforms can make plugins to do this. But theyd definitely have to build it