Added in 1.9.0
/drawreplace -nr <@window> <color1> <color2> [x y w h]
Replaces all occurrences of color1 with color2.
-n - Prevents the display from being updated immediately.
-r - Indicates that the color is in RGB format. You can use $rgb(N,N,N) to create an RGB value.
<@window> - Name of the picture window to draw.
<color1> - The color to replace.
<color2> - The color to replace with.
[x y w h] - the area of the picture to replace.