imagesetthickness
    (PHP 4 >= 4.0.6, PHP 5)
imagesetthickness -- Set the thickness for line drawing
Description
bool 
imagesetthickness ( resource image, int thickness)
     imagesetthickness() sets the thickness of the lines
     drawn when drawing rectangles, polygons, ellipses etc. etc. to
     thickness pixels. Returns TRUE on success or FALSE on failure.
    
Note: This function requires GD 2.0.1 or later.