I've made the image and saved it at artifacts/image.png: a 512 × 512 PNG (8-bit RGB). It's left out of the commit as required; .git/info/exclude already ignores artifacts/.

What it shows: a steel-coloured (#8a8f96) bug seen from the front, chest up and centred. It has two antennae with phosphor-green tips, sleepy eyes with heavy black lids, pink cheeks and small mandibles. It wears a cobalt hoodie with navy shading, a centre zip line, bone drawstrings and a pocket, and it has no headgear. The shoulders reach the bottom edge.

How it was made: I drew it on a 32 × 32 grid with a script, tools/draw_iu0571.py, using only Python's standard library. Every shape has a black outline one grid square thick, and the grid is scaled up 16× with hard square pixels. I used the script instead of the image-generation tool so the grid, outlines and palette would come out exactly right.

Checks:

• Size and format: the file command reports a 512 × 512 PNG. I couldn't run ffprobe because it isn't installed on this machine.
• Colours: a scan of every pixel found exactly 9 colours: the #0c1610 background, black outline, steel, bone, cobalt, navy, phosphor, bubblegum, and moss for 5 small background specks.
• No extras: there's no text, frame, gradient or anti-aliasing.

Limitations: I don't know of any unmet requirement. The figure's side outlines stop one grid square short of the left and right edges. No person has checked whether the style matches the rest of the 787-piece set.

I committed the script and a README.md describing the result and these limitations. Git had no author set on this machine, so the commit (159c956) lists you (satoshi721@protonmail.com) as author.