How to center image in PDF (fpdf) using Image() in PHP....

Hi! I tried out the Free PDF Library for creating the PDF at www.fpdf.org and it showed the php function, Image() and I read the documentation on this Image() on what paramenters are being used inside this function but what I found instead is that the X,Y coordinate is specified only from the upper-left corner. So, the question is how do I know what is the total width of a page in PDF, so I can whip up a php code to give me the center code of an image and enter it into the Image() function. The document showed... --snip-- Image(string file, float x, float y, float w [, float h [, string type [, mixed link]]]) --snip-- Thanks... Scott F.