Sets the width of the overlay image.
This operation occurs after your initial image has been resized. Values can range from
0 to the width of the overlay image, and can be larger than the width of the base image if desired. Note:
bw is not applicable to color or text overlays—color overlays apply to the entire image, and text overlay padding can be controlled with the
See the API specification for more information about this parameter's value ranges and format.