gd2 ser mærkeligt ud

Kode 

<?php
	
	$img_w = (isset($_GET["w"]) && $_GET["w"]!=0)  ? abs(intval($_GET["w"])) : 25;
	$img_h = (isset($_GET["h"]) && $_GET["h"]!=0)  ? abs(intval($_GET["h"])) : 115;
	$img_t = (isset($_GET["t"]) && $_GET["t"]!="") ? $_GET["t"]              : "Ingen parametre";
	
	$img = imagecreate($img_w,$img_h);
	
	$img_bg = imagecreatefromgif("_img/button_bg.gif");
	$img_left = imagecreatefromgif("_img/button_left.gif");
	$img_right = imagecreatefromgif("_img/button_right.gif");
	
	imagesettile($img,$img_bg);
	
	imagefilledrectangle($img,0,0,$img_w,$img_h,IMG_COLOR_TILED);
	
	imagecopy($img,$img_left,0,0,0,0,imagesx($img_left),imagesy($img_left));
	imagecopy($img,$img_right,imagesx($img)-imagesx($img_right),0,0,0,imagesx($img_right),imagesy($img_right));
	
	$ft_size = 1;
	
	while(true) {
		
		$corners = imagettfbbox($ft_size+1,0,"arial.ttf",$img_t);
		$c_x1 = $corners[0];
		$c_y1 = $corners[1];
		$c_x2 = $corners[2];
		$c_y2 = $corners[3];
		$c_x3 = $corners[4];
		$c_y3 = $corners[5];
		$c_x4 = $corners[6];
		$c_y4 = $corners[7];
		
		if(abs($c_x3-$c_x1)<imagesx($img)-8
		&& abs($c_y3-$c_y1)<imagesy($img)-8) {
			$ft_size++;
		} else {
			break;
		}
		
	}
	
	$corners = imagettfbbox($ft_size,0,"arial.ttf",$img_t);
	$c_x1 = $corners[0];
	$c_y1 = $corners[1];
	$c_x2 = $corners[2];
	$c_y2 = $corners[3];
	$c_x3 = $corners[4];
	$c_y3 = $corners[5];
	$c_x4 = $corners[6];
	$c_y4 = $corners[7];
	
	$x = intval(imagesx($img)/2 - abs($c_x3-$c_x1)/2 + 1);
	$y = intval(imagesy($img)/2 + abs($c_y3-$c_y1)/2 - 1);;
	
	imagettftext($img,$ft_size,0,$x,$y,imagecolorallocate($img,51,51,51),"arial.ttf",$img_t);
	
	header('Content-type: image/gif');
	
	imagegif($img);
	imagedestroy($img);
	imagedestroy($img_bg);
	imagedestroy($img_left);
	imagedestroy($img_right);
	
	
?>