Well you could take a screen of the minimap, make it old-like in photoshop or whatever and then import it somehow(not sure what the path is, but I know it's doable, I saw a few maps that had a dragon or something on the minimap).
Make your map. Take a screenshot of your map. Open it up in photoshop and make another layer. Draw in however you want the islands. Remove the bottom layer. Paste in whatever map backing you want. Save. Export to whatever file type is needed.
Import to map as minimap. Then win.
are you yelling at me because i gave you an idea? that doesnt seem very nice
also if you dont explore it yet could it just be the yellowish paper if it anit explored yet and then when you explore it you see the clifts?
i need the yellowish paper if its just black its no true PIRATE MAP. could you like find the black thing and reskin it to it be like old paper. FOLLOW THE RED LINE TO THE X AND YOU HAVE FOUND YOUR GOLD ARG