Affiche d'index de couleurs en pixels (Photo en affiche de blocs de couleurs pixélisés)

Use a single real photograph as the only content source to create a vertical before-and-after comparison poster. The upper half fully preserves the real photographic texture, subject identity, quantity, pose, spatial relationships, lighting, and composition of the input photo, without turning the photo into an illustration; the lower half is a stylized re-rendering zone of the same photo: on a warm white paper surface, distill the image into four equal-sized square pixel color index blocks, corresponding respectively to the most recognizable subject silhouette, architectural or object structure, primary color and light-shadow relationship, and one environmental detail from the photo. Each block uses a limited color palette with hard-edged pixel blocks and a low-resolution grid feel, retaining traceable forms without random mosaicking. Arrange the four blocks in a 2x2 grid, leaving ample paper margin around them; use thin black cross crop/registration marks to frame the index area, and add a minimal amount of small bilingual titles and fields, such as "COLOR INDEX / SCENE STUDY", with restrained, clear text like print proof annotations that do not overpower the design. The lower half must look like a designed color index card, not a filter, ordinary pixelation, or repeated photo; do not add unrelated objects or alter the photo's subject. The upper and lower areas each occupy about half, with a clear horizontal boundary; side-by-side layouts, multi-image collages, "original/AI image" corner labels, watermarks, and brand logos are prohibited. All colors are extracted and compressed from the input photo, and the content of the four blocks varies with the photo's subject, applicable to any photo including people, animals, architecture, street scenes, nature, interiors, food, and objects.