CUR to JPG Converter

Encoding: the CUR uses BMP or PNG images inside an icon directory; JPG uses lossy DCT coding in 8×8 pixel blocks, with colour usually stored at half resolution, and the download is a standard JPEG at the quality you choose.

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

Colour: RGB or a palette in the CUR; JPG supports YCbCr shown as RGB, greyscale, or CMYK from print software, 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 JPG has none, so transparent areas are filled with the colour you choose.

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; JPG can carry EXIF (camera, date, GPS), XMP, IPTC and an ICC profile in APP segments, 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.

JPEG is the universal photo format. It compresses by discarding fine detail the eye is least sensitive to, which makes photos small but blurs sharp edges and text if pushed too far.

A JPEG starts with the bytes FF D8 and is a run of marker segments: APP1 carries EXIF and often a thumbnail, APP2 an ICC profile, DQT the quantization tables that decide the quality, and SOS the compressed scan, which ends at FF D9.

JPG is the better choice for photographs that need to open anywhere, while CUR suits custom mouse cursors.

JPG strengths: Opens everywhere: every browser, phone, camera, printer and app; Small files for photographs; Adjustable quality from tiny to near-lossless. Drawbacks to weigh: No transparency; Lossy: every re-save loses a little more; Blocky artifacts around text, logos and sharp lines.