progressive JPEG
A progressive JPEG is the JPEG equivalent of the interlaced GIF Graphics Interchange Format . It's an image created using the JPEG suite of compression algorithms that will "fade in" in successive waves of lines until the entire image has completely arrived. Like the interlaced GIF, a progressive JPEG is a more appealing way to deliver an image at modem connection speeds. Users with faster connections are not likely to notice the difference.
This was last updated in April 2005