Online Batch Image Blur Tool

Online Batch Image Blur Tool

Batch blur tool with seven modes: Stack Blur (default), Gaussian Blur, Motion Blur, Box Blur, Radial Blur, Heavy Radial Blur and Soften. It processes up to 30 selected images with one shared set of options and keeps each image's original pixel dimensions.

Stack Blur uses separable triangular weights horizontally and vertically, with radius 1–180 (default 10) and repeated border pixels. For Stack, Box and Soften, colors are weighted by alpha before averaging and converted back afterward, so transparent pixels do not contribute unweighted hidden colors. Box Blur uses uniform weights at fixed radius 1 (3 × 3). Soften uses uniform weights with a 3 × 3 or 5 × 5 mask, corresponding to radius 1 or 2.

Gaussian Blur exposes kernel size 3-13, default 5. The implementation maps it to browser canvas blur radius max(1,(kernel-1)/2) and pads the source by repeated edge strips before cropping back to the original dimensions.

Motion Blur exposes angle 0-359 degrees, default 45. It composites 21 shifted samples along that direction over a distance max(8 pixels, 3.5% of the shorter image side). This is a fixed sampled motion effect; there is no separate distance or sample-count control.

Radial Blur exposes size 1-100%, default 50; strength 1-100, default 10; and horizontal/vertical centers from -1 to 1, default 0. Center 0/0 means the image center. It composites rotated samples and clips the effect to a circle whose radius is half the image diagonal times size percent. Heavy Radial uses 41 samples and maximum angular spread 0.34 radians without the circular clip; its strength is fixed at 100.

Worked example: apply Stack Blur radius 10 to a sharp landscape and portrait to soften both with the same neighborhood radius. For a directional alternative, Motion Blur at 45 degrees uses 21 samples along the diagonal. The output dimensions remain those of each source, so the same radius has a different relative visual scale on differently sized images.

Each file must have an image MIME type, be no larger than 25 MiB and decode to no more than 24,000,000 pixels. The selected batch is capped at 100 MiB and 40,000,000 decoded pixels. The interface lists PNG, JPEG, WebP, GIF and BMP, subject to browser decoding support.

Every result is encoded as PNG and named from the original base name plus -blur.png. Download all starts separate downloads about 180 ms apart, not a ZIP. Processing is local in the browser; Generate must be pressed after option changes. Face detection, selective masks, background-only blur and live previews are unavailable. Output formats and metadata preservation are not configurable.