[gpmcadam]

FYI Markup, a feature of the Photos app in iOS can essentially do this fairly trivially.

https://support.apple.com/en-gb/HT206885

[kemayo]

True, but it's honestly pretty fiddly. If you want to do exactly-this, adding an emoji is a pain because you have to jump through a few hoops to resize it -- pinch-dragging doesn't work.