VS Code extension icon: 128x128 minimum, 256x256 for retina

The VS Code extension manifest page says the icon must be at least 128x128, and recommends 256x256 for retina displays. Neither is a size GPT Image 2.5 will return on Sume, since both are under the 655,360 pixel floor. Request 1024x1024 and scale it down to 256x256.

VS Code's facts are from its manifest reference; Sume's from the Image API docs. Both read 2026-10-01.

What does the manifest say?

The icon field in package.json points to an image file, such as images/icon.png. The page gives a 128x128 minimum and 256x256 for retina. It also describes a galleryBanner with a color and a light or dark theme for the Marketplace header.

Why 1024x1024?

It satisfies Sume's GPT custom-size limits (edges multiples of 16, 1,048,576 pixels) and is exactly 4x the 256 retina size, so the downscale is a clean factor of 4 (our arithmetic).

What do I send?

Pick a simple mark with strong contrast; fine detail disappears at 128 pixels.

curl -X POST https://api.sume.com/v1/images \
  -H "Authorization: Bearer $SUME_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "openai/gpt-image-2.5",
    "prompt": "Extension icon: bold geometric braces symbol in white on a solid deep green background, flat",
    "image_size": "1024x1024",
    "output_format": "png"
  }'

Is the Marketplace banner a separate image?

No. galleryBanner is a color and a theme in the manifest, not an uploaded picture, so there is nothing to generate for it.