create a dither script for adding retro look to photos

dither.py

@@ -0,0 +1,96 @@
+#!/usr/bin/env python3
+"""
+dither.py — Retro photo processor for Dangerous Wonder
+
+Converts JPGs in photos/ to palette-reduced, ordered-dithered PNGs
+using the 216 web-safe color palette. Skips already-processed PNGs.
+
+Usage:
+    python3 dither.py              # process all unprocessed photos
+    python3 dither.py --force      # re-process everything from backups
+    python3 dither.py --help       # show usage
+"""
+
+import argparse
+import os
+import shutil
+import sys
+from PIL import Image
+
+PALETTE_BYTES = []
+for r in range(0, 256, 51):
+    for g in range(0, 256, 51):
+        for b in range(0, 256, 51):
+            PALETTE_BYTES.extend([r, g, b])
+
+PALETTE_IMG = Image.new("P", (1, 1))
+PALETTE_IMG.putpalette(PALETTE_BYTES + [0, 0, 0] * (256 - 216))
+
+SCRIPT_DIR = os.path.dirname(os.path.abspath(__file__))
+PHOTOS_DIR = os.path.join(SCRIPT_DIR, "photos")
+BACKUP_DIR = os.path.join(SCRIPT_DIR, "photos-backup")
+
+
+def process_image(src_path, dst_path):
+    img = Image.open(src_path).convert("RGB")
+    quantized = img.quantize(palette=PALETTE_IMG, dither=Image.Dither.ORDERED)
+    quantized.save(dst_path, "PNG", optimize=True)
+    orig_kb = os.path.getsize(src_path) // 1024
+    new_kb = os.path.getsize(dst_path) // 1024
+    print(
+        f"  {os.path.basename(src_path)} -> {os.path.basename(dst_path)}  "
+        f"({orig_kb}KB -> {new_kb}KB)"
+    )
+
+
+def ensure_backup(src_path):
+    os.makedirs(BACKUP_DIR, exist_ok=True)
+    dst = os.path.join(BACKUP_DIR, os.path.basename(src_path))
+    if not os.path.exists(dst):
+        shutil.copy2(src_path, dst)
+
+
+def main():
+    parser = argparse.ArgumentParser(
+        description="Convert photos to web-safe palette with ordered dithering"
+    )
+    parser.add_argument(
+        "--force", action="store_true", help="Re-process all images from photos-backup/"
+    )
+    args = parser.parse_args()
+
+    if args.force:
+        jpgs = sorted(
+            f for f in os.listdir(BACKUP_DIR) if f.lower().endswith((".jpg", ".jpeg"))
+        )
+        if not jpgs:
+            print("No JPG files found in photos-backup/")
+            sys.exit(1)
+        src_dir = BACKUP_DIR
+        print(f"Re-processing {len(jpgs)} images from backup...\n")
+    else:
+        jpgs = sorted(
+            f for f in os.listdir(PHOTOS_DIR) if f.lower().endswith((".jpg", ".jpeg"))
+        )
+        if not jpgs:
+            print("No new JPG files to process in photos/")
+            sys.exit(0)
+        src_dir = PHOTOS_DIR
+        print(f"Processing {len(jpgs)} new image(s)...\n")
+
+    for fname in jpgs:
+        src = os.path.join(src_dir, fname)
+        ensure_backup(src)
+
+        png_name = os.path.splitext(fname)[0] + ".png"
+        dst = os.path.join(PHOTOS_DIR, png_name)
+        process_image(src, dst)
+
+        if src_dir == PHOTOS_DIR:
+            os.remove(src)
+
+    print(f"\nDone. Originals in photos-backup/, dithered PNGs in photos/.")
+
+
+if __name__ == "__main__":
+    main()