Draw over background image, can return both of the background and the drawing.

Parameters input :

brushSize : Size of the brush in string.

brushColor : Color of the brush. Use javascript color.

imageInputBase64 : Background image, in base 64

imageWidth : Targeted background image width, if left empty, will use current image width.

imageHeight : Targeted background image height, if left empty, will use current image height.

Client action "DrawToImage" will return combined background image with drawing as base64.