CUR to WebP Converter

Encoding: the CUR uses BMP or PNG images inside an icon directory; WebP uses lossy VP8 coding or lossless VP8L, and the download is a lossy WebP at the quality you choose (lossless under More options), keeping transparency.

Bit depth: 1 to 32 bits per pixel in the CUR; WebP allows 8 bits per channel, and the WebP written here has 8 bits per channel.

Colour: RGB or a palette in the CUR; WebP supports RGB; lossy WebP stores colour at half resolution (4:2:0), written here as 8-bit sRGB.

Transparency: the CUR stores it as 8-bit alpha in 32-bit entries, or a 1-bit mask; the WebP keeps it as a separate alpha plane, available in lossy as well as lossless files.

Other images: the CUR can hold one or more cursor sizes; only the main image is converted.

Metadata: the CUR can carry only the hotspot coordinates; WebP can carry EXIF, XMP and ICC chunks, but nothing is copied across.

CUR is the ICO container with a click hotspot, used for custom Windows mouse cursors and CSS cursors.

A CUR file has the same layout as an ICO, but its type field is 2 and each directory entry stores the hotspot (the pixel that registers the click) where an ICO stores colour planes and bit depth.

CUR files usually come from custom Windows cursor packs and CSS cursor files.

WebP is Google's web image format. It supports lossy and lossless compression, transparency and animation, and is typically 25 to 35 percent smaller than JPEG at the same visual quality.

A WebP is a RIFF file: 'RIFF', a length, 'WEBP', then chunks. A simple lossy file is one VP8 chunk and a lossless one is VP8L; the extended VP8X header announces alpha, animation, ICC, EXIF or XMP chunks.

WebP is the better choice for images on websites and in apps, while CUR suits custom mouse cursors.

WebP strengths: 25-35% smaller than JPEG; Transparency and animation in one format; Supported by every modern browser. Drawbacks to weigh: Some older desktop apps and photo printers cannot open it; Max 16383 px per side.