You
can edit colors in the color table to produce special effects, or
assign transparency in the image to a single color in the table.
Open the indexed-color image.
Choose Image > Mode > Color Table.
Click or drag within the table to choose the color or
range of colors you want to change.
Choose a color from the Color Picker or sample a color
from the image.
If you are changing a range of colors, Photoshop Elements creates a gradient in the color
table between the starting and ending colors. The first color you
choose in the Color Picker is the beginning color in the range.
When you click OK, the Color Picker reappears, so that you can choose
the last color in the range.
The colors you selected in the
Color Picker are placed in the range you selected in the Color Table
dialog box.
Click Preview to view the results of the changes you
have made to the image.
Click OK in the Color Table dialog box to apply the new
colors to the indexed-color image.