Upload an image to straighten
Accepted formats: JPG, PNG, WEBP, BMP, GIF (non-animated)
Paste (Ctrl/⌘+V) or drop an image — or import from a URL
Perspective correction — also called keystone correction — fixes the converging lines you get when you tilt the camera: photograph a tall building looking up and its vertical edges lean inward; shoot a document or whiteboard at an angle and its rectangle becomes a trapezoid. Image Machine's perspective tool applies a true projective transform (a homography, the same maths a perspective-control lens performs optically), so straight lines stay perfectly straight as you square the image up — it is not a simple stretch or skew. Two sliders drive it: Vertical fixes top-vs-bottom convergence, Horizontal fixes left-vs-right. Both start at zero, so an uploaded image is untouched until you adjust; the image centre stays fixed as a pivot, and any area the correction pulls in from beyond the original frame is left transparent so you can crop cleanly afterwards. It all runs locally in your browser with exact maths — no quality loss, no watermark, and your photo never leaves your device.
How It Works
Choose a tool
Pick from 120+ tools to resize, convert, compress, or enhance your image.
Upload & edit
Drag and drop your image and adjust the settings. It stays on your device.
Download
Save your result instantly — no watermark, no sign-up required.
Why Image Machine?
Your files never leave your device
All processing runs locally in your browser. Your images are never uploaded to a server.
Completely free
Every tool is free, with no limits, no watermarks, and no hidden costs.
Lightning fast
No upload waiting — your images are processed instantly on your own device.
Professional quality
Pixel-perfect output with full control over format, size, and quality.
Frequently Asked Questions
What is keystone / perspective correction?
Keystone correction fixes the converging lines that appear when the camera is tilted up or down (or left or right). A building photographed from below seems to lean back, its vertical edges angling inward; perspective correction straightens those edges so the building looks upright.
Is this a real perspective transform or just a stretch?
It is a true projective transform (a homography) — the same kind of warp a tilt-shift or perspective-control lens performs optically. Straight lines stay straight and the image squares up correctly, unlike a simple stretch or skew that would bend the geometry.
Why are the corners transparent after I adjust?
When you correct perspective, some areas of the output are pulled in from beyond the edge of the original photo. Those areas have no image data, so they are left transparent — just crop the result to the rectangle you want.
Is my photo uploaded anywhere?
No. The perspective correction is computed entirely in your browser with the Canvas API — your image is never uploaded, there is no sign-up, and the tool keeps working offline once the page has loaded.