An image editor for an image processing system has a predefined set of system colors. Color pixel color index values for an image to be edited are stored in an image buffer. A color lookup register bank stores color values in respective registers for a predefined set of system colors. Each buffer index value corresponds to a lookup register having the specified color value. The image is thus displayed by indexing the image pixels to the lookup register bank for the color signal inputs to the display. A mouse is used to designate displayed colors that a user desires to modify in a region of the displayed image. Pixel position data corresponding to the designated colors is detected and hue, saturation and brightness (HSB) values are determined from the stored color values for the designated image pixels. A minimum range of values is determined for each of the HSB variables. A preselected color edit operation is applied to those image pixels having colors corresponding to HSB values within the respective minimum HSB ranges.