Image Cropper

Internally the cropper works on the source image loaded into a canvas, with a selection rectangle defined in source pixel coordinates. When you drag a handle, the tool updates the rectangle bounds and re-renders just the selection outline, the underlying image data is not touched until you export. Export writes the selected region to a new canvas at the crop's exact pixel dimensions, then encodes that canvas in the output format. Because the encode step runs once on already-final pixels, output quality at a given JPEG quality setting is indistinguishable from cropping the original in any other tool.

Aspect ratio locks are enforced geometrically: if you resize a 1:1 crop by dragging a corner, the opposite corner updates to keep width equal to height down to the pixel. For preset ratios like 9:16, the math is the same with a different coefficient (width = height * 9/16). Free-form mode releases this constraint, which is the right choice when you are cropping to match a specific display size that does not match any standard ratio, a 1184x628 Open Graph image, for example, is close to but not exactly 16:9.

One subtle thing worth knowing: browser canvas operations run in sRGB color space by default. If your source image has an embedded color profile, common for professional photo exports, the crop will display in sRGB and the color profile will be lost on export. For web use this is usually fine because almost all browsers and platforms assume sRGB anyway. If you are cropping for a print workflow that expects Adobe RGB or ProPhoto RGB, you will want to handle the crop in a color-managed desktop editor instead.