To limit your image to colors most monitors can display and to reduce file size, decrease the color depth of the image to 256 colors (8-bit). You can choose a Web-safe palette that assures your image displays properly on a variety of computer monitors.
To decrease the color depth to 256 colors:
To emphasize the importance of certain colors in the conversion, select an area of your image (optional).
Choose Image > Decrease Color Depth > 256 Colors (8-bit).
In the Palette group box, choose a palette option. See About Palette Options.
In the Reduction method group box, choose a color reduction method. See About Color Reduction Methods.
Note: The Ordered Dither option is available only for the Standard/Web-safe color palette.
In the Options group box, mark or clear these check boxes:
Boost marked colors by If you selected an area of your image and you are using the Optimized Median Cut method, mark this check box to make the colors in the selection more important by a factor from 1 to 10. The selected colors will stand out from the rest of the image.
Include Windows’ colors If you chose the Optimized Median Cut or the Optimized Octree palette, you can mark this check box if you want the 16 standard Windows colors included in the converted image’s palette.
Reduce color bleeding If you chose the Optimized Median Cut or the Optimized Octree palette and the Error Diffusion reduction method, you can mark this check box to make the left-to-right bleed effect of colors less noticeable.
Click OK.
Understanding Color and Color Models
How Monitor and Print Colors Differ
Making a Palette Color Transparent