iPhone 18 Pro screenshot size: 1206x2622 and 1179x2556

The 6.3-inch display, which now lists iPhone 18 Pro, takes screenshots of 1179 x 2556 or 1206 x 2622 pixels, plus the rotated forms. Neither fits Sume's custom-pixel rules directly: neither pair is made of multiples of 16 (the GPT custom-size rule), and both long edges are over the 2160 Timeline cap. Generate near the shape and scale to Apple's exact pixels as a final step.

Sizes are from Apple's screenshot specifications, read 2026-10-01; Sume rules from https://docs.sume.com/models/images and https://docs.sume.com/models/timeline.

What exactly fails for each size?

Each size against the two Sume routes.

Do the rotated sizes help?

No. 2556 x 1179 and 2622 x 1206 swap the edges, so the same numbers fail: 2556 and 2622 are over 2160 for Timeline, and neither pair is a multiple of 16.

What should I do instead?

Choose a custom image_size with both edges multiples of 16, a max edge of 3840, aspect at most 3:1 and 655,360-8,294,400 pixels, in the same portrait shape, then scale to Apple's exact pixels yourself. The custom sizes post lists the rules, and the upscale post says what Sume's upscale does not promise.

Is there a 6.9-inch version of this?

Yes, with different numbers and the same outcome. See the iPhone 18 Pro Max sizes.