Straighten a Crooked Photo Automatically — Every Setting Explained (Free, No Upload)

Every setting of the free Image Straightening tool: Auto-Detect Rotation finds −3.9° on a Lisbon facade turned 4° (it also runs by itself when a photo opens); Crop to fill keeps 82% of the frame, Keep everything grows it to 3545 × 2355 with filled corners; drag a line along anything level; the slider and number box; turns and flips. Then three jobs: a leaning photo, a crooked scan (−3.4°, kept whole as a JPG with white corners) and a photo of people where it will not guess and you set −3° yourself. Nothing is uploaded.

Image Straightening, every setting, on a photo of a house in Lisbon that leans four degrees. Auto-Detect Rotation — which also runs by itself the moment a photo opens — looks for the lines that should be straight — the door, the windows, the rows of tiles — and here finds −3.9°. Turning a photo leaves empty corners, so Crop to fill trims them and tells you the cost (82% of the frame kept); Keep everything grows the frame instead and fills the corners, transparent in a PNG and white in a JPG. You can also drag a line along anything that should be level, or set the angle to a tenth of a degree with the slider or the number box; quarter turns and flips are applied first. On a crooked scan it finds −3.4° from the lines of text. And on a photo of people, with nothing that has to be level, it does not guess: "No clear horizon — set the angle yourself". Free straightens one image at a time up to 25 MB. Nothing is uploaded.