(PHP 4 >= 4.0.6, PHP 5)
imagesetthickness — Set the thickness for line drawing
imagesetthickness() sets the thickness of the lines drawn when drawing rectangles, polygons, ellipses etc. etc. to thickness pixels.
An image resource, returned by one of the image creation functions, such as imagecreatetruecolor().
Returns TRUE on success or FALSE on failure.
Note: This function requires GD 2.0.1 or later (2.0.28 or later is recommended).