Web Design in a Nutshell, 3rd Edition

Selective Quality (Fireworks)

Fireworks has a function called Selective Quality that works similarly to Photoshop’s Weighted Optimization by allowing you to compress different areas of a JPEG at different levels.

To compress selected areas of a JPEG, select an area of the image and choose Modify → Selective JPEG → Save Selection as JPEG Mask. In the Optimize panel, click the edit icon next to Selective Quality and enter the compression value in the box. Entering a low value compresses the Selective JPEG area more than the rest of the image. Entering a high value compresses the Selective JPEG area less than the rest of the image. You can also elect to preserve quality of text items and/or button quality, automatically exporting them at a higher quality level.