Image Compressor

About image compression

Image compression trades a small amount of visual quality for a much smaller file, and it's one of the simplest ways to make a web page, email attachment or chat upload noticeably faster to send and load. JPEG achieves this by discarding fine detail the human eye barely notices, PNG relies on lossless pattern-matching that benefits enormously from a simpler, more repetitive image, and GIF stores every pixel as an index into a limited color palette rather than a full 24-bit color value.

The three formats suit different kinds of images. JPEG's adjustable quality setting works best on photos and other images with smooth gradients, where a little quality loss is invisible at normal viewing sizes. PNG and GIF are built around a limited color palette, so they shine on screenshots, logos, icons and flat-color illustrations — reducing how many distinct colors an image uses shrinks the file dramatically with very little visible change on that kind of artwork, though the same reduction can look noticeably banded on a detailed photo.

Scaling an image down before compressing it is one of the most effective size reductions of all, since a page or chat rarely needs a picture larger than the space it will actually be displayed in. Combining a modest resolution with a sensible quality or color setting for the format usually cuts file size to a fraction of the original while keeping the result perfectly presentable.