Shopify's recommended 2048 x 2048 product image with gpt-image-2.5

Shopify's product media page lists 2048 x 2048 pixels as the recommended image size. On Sume that is a valid custom image_size for openai/gpt-image-2.5: 2048 is a multiple of 16, the 1:1 ratio is under 3:1, and 4,194,304 pixels sits inside the 655,360 to 8,294,400 range.

Does 2048 x 2048 pass Sume's custom size rules?

The Image API docs give four rules for a custom size on ChatGPT Image 2.5. Here is 2048 x 2048 against each.

What does the request look like?

Send image_size as 2048x2048. Omitted quality defaults to high on this model, and background takes auto, transparent or opaque.

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": "Leather wallet on a light grey backdrop, soft shadow, studio product photo",
    "image_size": "2048x2048",
    "background": "opaque",
    "output_format": "jpeg"
  }'

Is 2048 x 2048 a requirement?

No. Shopify's page read on 2026-09-30 calls it recommended, and states a maximum of 4472 x 4472 px and 20 MB. A smaller square works if you do not need to zoom.

What should I check after generation?

The response returns a Sume-hosted URL, and the docs state cost as the USD amount billed. Open the file to confirm the size and the product details; a generated image can change small features of a product, so compare it to the real item before you publish.