The image is at artifacts/image.png: a 512 × 512 PNG (8-bit RGB, about 4 KB). It's left untracked as the task asks, and the repo's own exclude rules already ignore artifacts/.

What it shows: a lagoon (#4ecac0) ghost head, front facing and centred, inside a cobalt hoodie that runs off the bottom edge. It has big eyes (bone whites, black pupils with a highlight), a small round mouth and pink cheeks. The hoodie has a navy hood lining, bone drawstrings and a navy pocket. There is nothing on the head, and no text, logo or frame.

How I checked it: I decoded the PNG in Python and viewed the render.

• Every 16 × 16 block is a single solid colour, so it's a true 32 × 32 grid scaled up with hard square pixels: no anti-aliasing, gradients or blur.
• The only colours are the background #0c1610, black outlines, and bone, moss, cobalt, navy, bubblegum and lagoon from the palette.
• The background is solid apart from six single-pixel moss specks.

Requirements not fully met (also listed in README.md):

• I drew it in code (tools/make_iu0370.py) instead of with the image-generation tool. That guarantees the grid and palette rules, but the art is fairly simple.
• With the hood over the head and the figure cut off at the shoulders, the ghost has no wavy tail or pointed top. It reads as a ghost from its colour, round head and face only.
• The black outline colour isn't one of the named palette colours, though the style rules ask for black outlines.
• I haven't compared it with the other pieces in the 787-piece set.

Not committed: git has no author name or email set on this machine, and I didn't want to make one up. README.md and tools/make_iu0370.py are therefore uncommitted in the working tree.