this is a function that is based on imagestring but it produces text in the center of an image i hope it helps :D
<?php
function ImageStringCenter($image_resource, $font_size, $line_number, $total_lines, $text, $color ) {
$center_x = ceil( ( imagesx($image_resource) - ( ImageFontWidth($font_size) * strlen($text) ) ) / 2 );
$center_y = ceil( ( ( imagesy($image_resource) - ( ImageFontHeight($font_size) * $total_lines ) ) / 2) + ( ($line_number-1) * ImageFontHeight($font_size) ) );
ImageString($image_resource, $font_size, $center_x, $center_y, $text, $color );
}
?>
