Background

Change the background of a generated part of the new image.

Also, any transparent color will be merged with a provided background color.

Often used with fill mutator to change a background color if an origin file was smaller then result.

Available prefixes: bg

Available v: ‘white’, ‘black’, ‘transparent’ or any hex color value

Examples: bg_4286f4 bg_black,fill_1000x1000 bg_white,fill_1000x1000