OneTaskBy Tim King · Updated
Blur Image Online
Brush Over Part of an Image or Blur the Background of a Photo
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How the Blur Image works
Blur image detail in a few seconds: soften the whole photo, brush over just the parts you want blurred, or brush over the subject and blur everything else for a quick background blur. The result downloads in the same format you dropped in.
How to blur image areas with the brush
Drop a photo in and set Apply to to Brushed areas. The preview turns into a canvas you can paint on: press, drag across the part to soften and let go. Each stroke is applied when you release the pointer, and you can keep adding strokes until everything you want is covered. Double-click the image to clear every stroke and start again. Strokes are remembered as proportions of the picture, so changing the strength or brush size afterwards re-renders the same areas rather than losing them.
Blurring the background instead
Choose Everything except brushed areas, then paint over the person or object you want to keep sharp. Everything you did not paint is blurred, which gives a rough version of the shallow depth of field a portrait lens produces. A larger brush and a strong radius work best; the edge of the brush is soft-cornered, so expect a slight halo rather than a cut-out outline.
What the strength slider means
The blur is three box blurs run back to back, which closely approximates a Gaussian blur with a spread of roughly the radius you choose. It is computed directly on the pixels rather than with the browser's CSS filter, so it looks identical in Chrome, Firefox and Safari. A radius of 3 to 6 px softens skin or noise; 20 px and above turns text and faces into indistinct shapes on a typical phone photo.
Blur is not redaction
Blurring hides detail from casual viewers but it is not a secure way to remove information. Blur is mathematically close to reversible, and blurred text has been recovered many times. For account numbers, names or anything sensitive, use a solid block in the image redactor instead.
Private by design
The photo is decoded and processed in your browser. Nothing is uploaded, and the downloaded file is re-encoded from a canvas, which also drops EXIF metadata such as GPS location.
FAQ
Can I blur only part of a picture?
Yes. Set Apply to to Brushed areas and paint over the parts you want softened. Each stroke is added when you let go, and double-clicking the image clears all of them so you can start over.
How do I blur the background of a photo?
Pick Everything except brushed areas and paint over the subject you want to keep in focus. The rest of the photo is blurred at the strength you set, which gives a simple portrait-style background.
Is blurring safe for hiding text or numbers?
No. Blur keeps enough information that text can often be reconstructed, especially at low strength. For anything sensitive, use a solid black or white block, which destroys the covered pixels entirely.
Does the blurred image keep its original format and size?
The output has exactly the same pixel dimensions as the source and keeps JPG, PNG or WebP format. Other formats such as HEIC are saved as PNG, and EXIF metadata is removed on the way out.
See also: all Images tools, Audio, Video & Screen, PDF, SVG, Simulations & Screensavers, Generative Art, Chart Makers, 3D Model Viewers, Drawing Pads, Mockups & 3D Making, Diagram Makers, 3D Science, Tracker Music.
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