Border Size Color
Draws a border around the image, in the width and color defined. The border will overlap the image rather than altering its size.
The default is no border, and the width and color values must be specified as a comma-separated list with the width first. Valid color values are 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,
See the API specification for more information about this parameter's value ranges and format.