Chat stickers!

Similar to what Telegram/WhatsApp has. In case you're unfamiliar with these, stickers are basically image packs of any kind, a bit similar to custom emojis but bigger and more organized. You could have the option of creating your very own sticker pack with your own images (a cropping tool could come in handy there if possible, discord) or save the sticker packs you have and use them anywhere you wish! An option to save you favorite stickers separately might be useful aswell.