Keystone Photo Lab

The perspective distortion you get when you tilt your camera up at a building: the vertical edges converge toward the top, so the building looks like it's leaning backwards. It's also called converging verticals or converging lines. Keystone corrects it automatically and fills the corners the correction leaves behind. Read the full guide.

It detects the converging lines in a photo and straightens leaning buildings, then uses generative AI to fill the empty corners that straightening leaves behind — at full resolution — so you keep the whole frame instead of cropping. It can also generatively expand, upscale, reimagine a shot in a new style, and fine-tune color with a full adjustment studio.

Correcting perspective warps the rectangular image into a trapezoid, leaving empty wedge-shaped gaps at the corners. Most editors crop those gaps away, losing part of the frame. Keystone generates only those empty corners — the rest of the photo is your original pixels, untouched, not an AI-regenerated copy — so your full composition is preserved.

Yes. Unlike editors that flatten to sRGB, Keystone preserves your iPhone's wide-gamut Display P3 color and native HDR gain map end to end, and saves as HEIF at the photo's native resolution. Even the metadata is preserved — EXIF, capture date and location travel with the photo.

Yes. It runs natively on Apple-silicon Macs and is available from the Mac App Store under the same listing as the iPhone app. On a Mac you can pick photos from any folder with the standard Open panel, resize the window, and zoom and pan with the trackpad or mouse wheel.

Keystone is free to download and you can start editing right away with no account. Optional subscriptions unlock more AI edits and are billed monthly or yearly through your Apple ID, cancellable anytime.

Subscriptions are managed through your Apple ID: open Settings, tap your name, tap Subscriptions, choose Keystone Photo Lab and cancel. You keep access until the end of the billing period.