GPT Image 2 city terrain-outline miniature island poster prompt

Generate a city-rendered digital art poster for {City Name}, using a 9:16 vertical composition. The core subject of the image is a miniature city island floating above the water, occupying most of the visual space. The outer contour of the island must strictly follow the real geographic outline / administrative boundary / map silhouette of {City Name}. The priority of the overall shape must be higher than landmarks, buildings, and decorative elements. First, generate an island shape that closely matches the…