Image types a Sume Format run accepts: JPEG, PNG, WebP, GIF, AVIF

A Format run takes images in five formats: JPEG, PNG, WebP, GIF and AVIF. Sume's Create a run page limits attachments to 30 images, 30 MB each and 500 MB in total (read 2026-10-04). Video, audio, PDFs and other file types are not accepted as attachments.

Phones and design tools often export something else, so the common failure is a HEIC or TIFF file that a user thought was an image.

What are the limits?

From the docs, read today:

How should I send them?

Each attachment is either a public HTTPS URL or an asset_id. The asset route goes through the Assets API, which is not in the public OpenAPI file, so prefer URLs a Sume worker can fetch without a login. A URL behind a sign-in page fails the fetch even though it works in your browser.

What do I do with HEIC or TIFF?

Convert before you send.

• Export HEIC as JPEG or PNG on the device, or convert on your server.
• Re-save TIFF as PNG for lossless, or WebP when size matters.
• Resize anything near 30 MB; a 4,000-pixel JPEG is usually well under.
• Count attachments before the call so a batch of 31 never reaches the API.