The JPEG file format (named for the Joint Photographic Experts Group) is designed to compress photographs or images with continuous-tone color, such as a color gradient. The JPEG format supports 24-bit color (millions of colors) and preserves the broad range of color and subtle variations in hue that characterize continuous-tone images.

The JPEG format reduces image file size by discarding some data from the file. Because some data is lost in the compression process, the JPEG format is referred to as lossy. When compressing an image as a JPEG, you choose a Quality setting to determine how much data is discarded and how much the file size is reduced.

Compressing an image as a JPEG can cause sharp edges to appear rough or jagged. You apply the Smoothing command to a JPEG to smooth rough edges created by the compression process.

The JPEG format does not support transparency. However, you can simulate background transparency in a JPEG by choosing a Matte color that exactly matches the Web page background color on which the JPEG will appear.

Note: JPEG is not the recommended file format for all images. If your image contains large areas of flat color, sharp detail (such as small type), or if you need to preserve true transparency, you should use the GIF file format. See Selecting the appropriate file format in Using Fireworks 3 or Fireworks online Help.

This tutorial leads you through these processes:

Selecting the JPEG file format

Selecting a Quality level

Smoothing the image

Using background matting

Choosing other JPEG options

Mary Burger and Randy Varnell Mary Burger Mary Burger is a Senior Technical Writer at Macromedia. She specializes in Macromedia Flash documentation. Randy Varnell Randy Varnell is an instructional media developer in Dallas. He has written about FreeHand and Fireworks for Macromedia since 1996, contributing to user manuals, online help, and Macromedia.com. 3/10/00 background, compression, download time, file size, GIF, image quality, JPEG, lossy, Matte color, optimizing, Optimize to Size, progressive JPEG images, Quality, Smoothing, Sharpen Edges, transparency