I have watched YouTube video about AI fitures in S24 ultra that can generate image from sketch using Spen. However I can't find the fiture, I just find the AI to move an object in the photo, but can not generate image.
If you want to generate picture from your sketch then take out you're s pen press the pen icon, press sketch to image and start drawing ( I'll attached screenshots) if you want to draw on image already taken then fallow @Glenntech suggestion.