This tool hides the parts of a photo you don't want to share. Drag a box over a face, a car number plate, a house number, a name on a screenshot or a document, and choose how to hide it: blur, pixelate, or a solid box in any colour. Draw as many boxes as you need, move and resize them, and check the live preview before you save. You can also blur or pixelate the whole picture, for a soft background or a teaser image.
The blur is calculated by the tool itself (three box-blur passes that approximate a Gaussian blur), so it looks the same in Safari, Chrome and Firefox. Strength is relative to the picture size, so the preview and the full-size download match. The saved file is re-encoded from the edited pixels, so the original EXIF data, including GPS location, is not carried over.
Limits: blur and pixelation reduce detail, they don't erase it completely. Light blur or small pixel blocks can leave large text readable, and pixelated text can sometimes be partly reconstructed. For anything sensitive, such as ID numbers, bank details or addresses, use the Solid box effect, which replaces those pixels entirely. Photos above about 16.7 megapixels are scaled down to that size.