Let people pay for premium stickers. Split between Telegram and the artists. Win-win-win. Line does this well (at least it did in the past, I’m not in Asia anymore)
You can easily imagine a shiny border that cannot be emulated easily. In any case it doesn’t really matter if some people can copy the content. As long as enough users are willing to pay for premium stuff, that’s good. And it’s definitely the case, lot of people are happy paying for cosmetic content when it’s done well.
I think algorithmically detecting paid stickers on upload can work. I needed to detect duplicate images for a pet project once and I've got satisfying results out of using perceptual image hashing. Building up a database of hashes for existing files takes time, but after that looking up an image to see if it's in the database is fast, and it handles some basic color transforms, as well as minor cropping.
I'm not sure whether this particular approach is feasible at the scale of Telegram. But I believe this arrangement can be a good income source without upsetting users the way ads might.
