I made artifacts/image.png: a 512 × 512 PNG of a front-facing frog bust. I drew it by hand on a 32 × 32 grid and scaled it up 16× with hard pixel edges.

What's in it:

• Swamp #7cc84a skin with moss cheek spots.
• Bulging eyes that glow phosphor #39ff6a, each with a bone sparkle.
• A cobalt cap with a navy brim and seam.
• A tangerine hoodie with rust folds, bone drawstrings and a front pocket. The shoulders reach the bottom edge.
• A thick black outline, on a solid #0c1610 background with 5 tiny moss specks.
• No text, logo, frame or border.

Checks: I read the file's bytes back in Python. It is a valid 512 × 512 8-bit RGB PNG, and every 16 × 16 block is a single colour, so there is no anti-aliasing, gradient or blur. It uses exactly 10 colours: 8 from your palette, plus the background colour and black. I also looked at the rendered image twice and fixed one misplaced eye sparkle between the two looks. ffprobe wouldn't start here, so the byte check stands in for it.

Not fully met or not checked (also noted in artifacts/README.md):

• The outline is pure black #000000, which isn't in the palette list. I used it because the style rules ask for a thick black outline.
• I couldn't check how well it fits the 787-piece collection, because no example pieces were provided.
• The head fills nearly the full width, so there's no background margin beside the cheeks.

The image is left untracked for upload as instructed, and nothing is committed. To rebuild it, run python3 tools/make_iu0237.py artifacts/image.png. The script uses only the Python standard library, so it needs no network or extra installs.

Files are in artifacts/:

• image.png
• README.md