Using weighted optimization

Weighted optimization lets you smoothly vary optimization settings across an image using masks from text layers, shape layers, and alpha channels. This technique produces higher-quality results in critical image areas without sacrificing file size. With weighted optimization, you can produce gradual variations in GIF, PNG-8, and WBMP dithering, lossy GIF settings, and JPEG compression. Weighted optimization also lets you favor colors in selected image areas when you generate a color table.

Related Subtopics:

About masks and weighted optimization
Using masks to modify JPEG quality
Using masks to modify GIF lossiness
Using masks to modify dithering
Using masks to modify color reduction