If OP is the author, I'd recommend one UX change - put the prompt above the sketchpad because the prompt seems to be stronger than the sketch in terms of what gets drawn.
Transforming wireframes into UI / graphics is top of my mind right now.
Anyway, I tried some weird cases like a double sun and the AI got very confused. https://imgur.com/a/BAH3666 I expected some confusion like a weird horizon, but the double palm is very strange.