Image Blur

📖 Tool Introduction

Image Blur is an in-browser softening tool designed for every situation where you want a frame to feel dreamy, out of focus or hidden: bokeh backdrops, blurred covers, and quick privacy masking of faces or license plates. Its core engine is a separable box filter. First it runs a horizontal sliding-window sum across every row, then a vertical sliding-window sum down every column; the two passes together produce an even neighborhood average. Because the sliding window is updated incrementally, its cost stays decoupled from the radius, so the slider remains fluid even at 60 pixels. To reach the smooth bell-shaped feel of a professional gaussian blur, the tool offers one, two or three stacked passes — the more passes you stack, the closer the frequency response gets to a true gaussian distribution. Upload a picture and drag the radius slider; the round gauge readout shows the current radius at all times, and radius zero gives you the untouched original so you can flip back and forth instantly. When the result looks right, one click exports a lossless PNG in which the transparent channel and the soft edges are both preserved naturally, and because every calculation happens inside your own memory, the photo never touches a server and nothing is logged. The interface follows the website theme and language, works on desktop and phone, and needs no account, no install and no waiting. In practice the tool covers several everyday needs: softening a busy background so a screenshot feels calmer, feathering a face or a license plate before sharing, giving a hero image a frosted-glass feel behind text, or recreating the shallow depth of field that phone cameras advertise. One pass is already smooth, two reads like a proper lens blur, and three reaches the soft dreaminess used in wedding photography. The sliding-window implementation never blocks the page — even at a large radius on a multi-megapixel photo it finishes in a few dozen milliseconds, so you can drag the slider back and forth and watch the image breathe. The export always matches the on-screen preview, and the transparent channel of a PNG is treated as part of the average, which is why feathered edges look natural rather than hard.

✨ Key Features

• Infinitely adjustable radius: 0 to 60 pixels with a clear gauge readout
• Separable box filter: horizontal and vertical sliding passes stay fast and even
• Stackable passes: 1×, 2× and 3× stacking approximates a gaussian feel
• Live preview: repaints instantly as you drag, what you see is what you get
• Transparency friendly: PNG alpha channels and edges are softened naturally
• Fully local: the image never leaves the browser, zero uploads, zero leaks

📝 How to Use

1. Click the top drop bar to upload, or drag an image straight onto it
2. Watch the center preview and drag the blur radius slider to taste
3. Pick a stack level among 1×, 2× and 3× for a closer gaussian feel
4. Drag the radius back to 0 whenever you want to compare with the original
5. Click Export PNG to save the blurred image to your device

⚠️ Notes

• Working size: huge photos are scaled to a 2048px long edge to keep the slider smooth
• Radius choice: use a small radius for gentle softening, a large one for backdrop bokeh
• Stack cost: three passes recompute the whole image three times, so very large files may lag slightly
• Export format: output is fixed lossless PNG, keeping the alpha channel intact
• Original stays safe: all math happens in memory, the local file is never modified