Transform each uploaded photo into a single, standalone high-end art poster per photo. Do not create a collage of multiple photos. The overall composition should be in a 3:4 vertical format, strictly divided into equal 50:50 halves at the top and bottom. The upper half should faithfully use the original photo, without altering the subject, terrain, architecture, texture, light, color, or positional relationships, and only add delicate color grading reminiscent of an architecture magazine or photo exhibition, along with a very subtle film grain. If necessary, the sky or surrounding environment can be naturally extended, but do not distort, move, or change the main subject...