Background Color
bg
The bg parameter allows you to fill in any transparent areas in your image with a color of your choice.
Valid color values are a color keyword or 3- (RGB), 4- (ARGB) 6- (RRGGBB) or 8-digit (AARRGGBB) hexadecimal values. The “A” in a 4- or 8-digit hex value represents the color’s alpha transparency. The default is transparent white, 0FFF. When outputting image formats that do not support transparency (such as JPEG), set this value to a non-transparent color.
bg also sets the background color for transparent areas defined by the pad parameter.