Steam capsule sizes: header, small, main, and vertical

Steam's four required store capsules are the header capsule at 920×430 pixels, the small capsule at 462×174, the main capsule at 1232×706 and the vertical capsule at 748×896. Screenshots must be at least 1920×1080 (16:9), and the optional page background is 1438×810. Every capsule needs a readable game logo or name, and a base capsule may show only game art, the game name and an official subtitle.

None of these sizes is a valid ChatGPT Image 2.5 custom size, so on Sume you generate the art at a valid size of the same shape, add your logo, and resize it. Steam's rules are quoted from the Steamworks pages Store Graphical Assets, Graphical Asset Rules and Content Survey; Sume facts come from the Image API docs. All were read on 2026-09-28.

What are the Steam capsule sizes?

Steam generates the 120×45 and 184×69 capsules from the small capsule, and bundles add a 707×232 bundle header. Steamworks also offers downloadable templates for sizing and text placement.

What can a Steam capsule show?

A base capsule is limited to game artwork, the game name and any official subtitle. Steam's rules in short:

• No review scores of any kind, no award names, symbols or logos, and no discount copy such as “On Sale Now”.
• No text or imagery promoting another product, including sequels, and no other text.
• Every capsule needs a readable logo or name, accurate dimensions and PG-13 appropriate artwork.
• Text about a major update, seasonal event or DLC goes only on an Artwork Override, limited to one month and localized into the game's languages.
• Steam says games that break these rules may get less visibility and can't be featured in official Steam sales and events.

How do I make capsule art with Sume?

Steam suggests using the key art and logo from your retail boxes or marketing. Send your key art to ChatGPT Image 2.5 in input_references (a public HTTPS URL; up to 16 references) and ask for the capsule's size from the table. The model draws a new image from the reference, so compare each result with your key art. Each request size has the Steam size's shape to within a pixel, so a plain resize lands on Steam's pixels; the header capsule's 1472×688, for example, is exactly 1.6 times 920×430.

• Ask for empty space where the logo goes, then place your real logo in an editor; Steam wants the logotype easily legible against the background.
• Steam says the small capsule's logo must stay readable even at the smallest size, which in most cases means it nearly fills the image.
• n returns up to 4 versions per call on this model today, each billed; usage.cost in the response is the USD amount.
• Results are Sume-hosted, signed URLs in data[].url, so download the files you keep.

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": "Store capsule art from the reference key art: the same hero and castle, recomposed for a wide frame, the upper left kept clear for the game logo, no text",
    "input_references": [
      { "type": "image_url", "image_url": { "url": "https://example.com/key-art.png" } }
    ],
    "image_size": { "width": 1472, "height": 688 }
  }'

Can I use AI-generated art on Steam?

Steam's store asset pages don't mention AI; their capsule rules apply to every capsule, however it was made. Steam's Content Survey asks you to describe AI-generated content that ships with your game and is consumed by players, such as artwork. Valve reviews that content like any other, including a check that your game is consistent with your marketing materials, so keep generated capsule art true to the game.

Screenshots are different: Steam says they should exclusively show the gameplay, not concept art or pre-rendered stills, so capture them from the game rather than generating them.