There are various screen capture tools that have post-capture annotation tools. I'm looking for one where I can insert, drag, and/or paste another image onto the captured image. For example, it could be useful to drag a meme or sticker-type icon (stars, hearts, etc) into the scene.
Skitch and Ember [1] are perhaps the two main OSX screen capture tools, but neither support this capability (nor did Ember's precursor, Little Snapper).