An easy way to send a 1-bit mockup PNG to the device without going through a build would be great during design work! Wrongly-sized images could just lock to top-left.
It could be entirely a tethered function, OR better yet, it could store images in a list for showing to others standalone on the device.
This would be most useful when we have actual hardware, but nice on the Simulator too.
Very nice! I hope they go into some kind of list or gallery. (Even when not showing to others, I'd be pondering my own designs and making decisions among options.)
If you want to look at edits in real-time (by streaming the content of a preview window in your graphics editor), maybe Playdate AntiMirror could be of help for you