Eyedropper: Click here to set foreground color, option click to set background color, double click to modify color if pseudocolor mode. Double arrow: Click and drag to adjust contrast or threshold or density slice.
Click to set foreground color to white. Option click to set background color.
Click to set foreground color to black. Option click to set background color.
Click to set foreground color to red (pixel value 1). Option click to set background color.
Click to set foreground color to green (pixel value 2). Option click to set background color.
Click to set foreground color to blue (pixel value 3). Option click to set background color.
Click to set foreground color to yellow (pixel value 4). Option click to set background color.
Click to set foreground color to cyan (pixel value 5). Option click to set background color.
Click to set foreground color to magenta (pixel value 6). Option click to set background color.