Description
bool 
imagefilledrectangle ( resource image, int x1, int y1, int x2, int y2, int color )
     imagefilledrectangle() creates a filled
     rectangle of color color in image
     image starting at upper left coordinates
     x1, y1 and ending
     at bottom right coordinates x2,
     y2.  0, 0 is the top left corner of the
     image.