iPhone Duo App Store screenshot size: outer and inner

Apple lists four iPhone Duo screenshot sizes: 1398 x 2034 and 2034 x 1398 for the outer display, 2007 x 2853 and 2853 x 2007 for the inner display. Sume can hit the two outer sizes exactly through a Timeline still plus a video_frames PNG. It cannot hit the inner sizes, because 2007 is odd and 2853 is over the 2160 Timeline edge limit.

Apple's page, read 2026-10-01, also says uploads for this device in App Store Connect open later this year, so there is nothing to submit yet. Sume rules are from https://docs.sume.com/models/images, https://docs.sume.com/models/timeline and https://docs.sume.com/models/video-frames.

Which iPhone Duo sizes can Sume output?

Each size against the two relevant Sume rules.

Why does the image API miss the outer sizes?

Custom image_size needs both edges to be multiples of 16. 1398 / 16 is 87.4 and 2034 / 16 is 127.1, so neither edge qualifies, even though the pixel count (about 2.84 million) sits inside the 655,360-8,294,400 range. See image sizes and aspect ratios for what the API does accept.

How do I render the outer display size?

Put a still in Timeline video[].source_url (stills are static holds), set output.width to 1398 and output.height to 2034 (or the reverse for landscape), use audio.mode silence with a short duration, and render. Then run video_frames with an at value inside the clip and format png. Leave max_edge out so the frame keeps the source size; the clamp range is 16-2160 and would only shrink it.

Check the source's aspect ratio first: the default fit is cover, which crops. The steps for extraction are in extract video frames.

What about the inner display?

Neither Sume route can produce 2007 x 2853 or 2853 x 2007. Generate at an allowed size with a similar shape and resize it in your own tooling, or wait: the sizes are not yet uploadable in App Store Connect. The exact pixel size post covers what Sume's upscale does and does not guarantee.