NES BG Dot Art Conversion Prompt

Prompt

【NES Final Specification / Fully Completed Version: BG-Only Algorithmic Pixel Art Conversion Prompt】  Convert this image into NES/Famicom hardware-spec BG pixel art by strictly executing the following mathematical and logical steps, without limiting it to any specific subject.  The purpose of this prompt is to satisfy the “constraints that are valid as BG on real NES hardware.” Purely NES-like visual styling is prohibited. Use only the BG layer, and do not use sprites at all.  ──────────────────────── 【Prerequisites (NES BG Implementation Rules)】 ──────────────────────── - Output resolution: 256 × 240 pixels - Layer used: BG only on NES - No sprites allowed - Do not perform transparency processing - Treat Index 0 of each palette as the NES universal background color - Make Index 0 common to all palettes - Assign the color with the largest total on-screen area to the universal background color - Allow color number 0 to be used as a normal drawing color as well  ──────────────────────── 【Step 1: Geometric Image Processing (Subject Priority / Non-Distorting Crop)】 ──────────────────────── 1. Set the target output size to 256 × 240 pixels 2. 반드시 maintain the original image aspect ratio - Scale up or down until the shorter side fits the target - Image stretching is strictly prohibited 3. Automatically detect the main subject in the image (person, animal, building, etc.), and adjust the crop position so the main subject fits within the frame as much as possible 4. If no main subject can be detected, crop based on the center of the image  ──────────────────────── 【Step 2: Tile Decomposition and Attribute Block Definition (NES-Compliant)】 ──────────────────────── 1. Divide the image into 8×8 pixel tiles 2. Treat 2×2 tiles (16×16 pixels) as one attribute block 3. Apply all subsequent palette and color constraints on an attribute-block basis  ──────────────────────── 【Step 3: Attribute-Block-Level Palette Clustering (Maximum 4 Groups)】 ──────────────────────── 1. Analyze the color distribution within each 16×16 attribute block 2. Cluster all attribute blocks by similarity in color distribution and classify them into up to 4 groups 3. If a hue (such as blue or green) is clearly different from other areas, treat it as an independent group whenever possible 4. However, the NES BG subpalette must be limited to a maximum of 4, and priority should be given to the main su...