Use the Draw | Image | Colors | Convert
Depth command
to reduce
the image color depth to 256 colors or grayscale. This feature is useful
when the file size is very large. Converting the image color depth reduces
the memory overhead and allows the program to process information more
quickly.
Choose 256 colors to convert the selected image to 256 colors, or click the Grayscale button to convert the image color depth to eight shades of gray.
See Also