thank you... the problem was that i just turned my brain on yet ;-)
the factor i used was: $factor = $newWidth * $Pic[ 0 ][ ImgWidth ];
but i want to resize, so the factor should be this: $factor = $newWidth
/ $Pic[ 0 ][ ImgWidth ];
after debugging my $factor the newWidth and newHeight parameters for
the imagecreatetruecolor command were correct!