[PHP] izris slike v različnih formatih

<?php
// The file
//$filename = 'img/spring.jpg';
if(isset($_GET["f"]))
	$filename=$_GET["f"];
else
	$filename = 'img/spring.jpg';
	
if(!isset($_GET["w"])){
	if(isset($_GET["per"]))
		$percent = $_GET["per"];
	else
		$percent = 0.75;
}
	
// Content type
$mime = image_type_to_mime_type (exif_imagetype ($filename));
header('Content-Type: '.$mime);

// Get new dimensions
list($width, $height) = getimagesize($filename);

if(isset($_GET["w"])){
	$new_width = $_GET["w"];
	$percent = $new_width/$width;
}else{
	$new_width = $width * $percent;
}
$new_height = $height * $percent;

// Resample
$image_p = imagecreatetruecolor($new_width, $new_height);

if($mime="image/jpg")
	$image = imagecreatefromjpeg($filename);
elseif($mime="image/png")
	$image = imagecreatefrompng($filename);
elseif($mime="image/gif")
	$image = imagecreatefromgif($filename);
	
imagecopyresampled($image_p, $image, 0, 0, 0, 0, $new_width, $new_height, $width, $height);

// Output
if($mime="image/jpeg")
	imagejpeg($image_p, null, 100);
elseif($mime="image/png")
	imagepng($image_p, null, 100);
elseif($mime="image/gif")
	imagegif($image_p, null, 100);
	
imagedestroy($image_p);
?>

Problem imam pri izrisu različnih formatov. PNG in GIF mi noče izrisati. Kje sem naredil napako. Hvala!

V prvi datoteki kličem ...

	<div style="background-image:url('v2.php?w=250<?php echo '&f='.$filename; ?>'); background-color:#FFFFFF; background-position:center; background-repeat:no-repeat; width:500px; height:500px; box-shadow:1px 1px 6px #666666; border:#FFFFFF 0px solid; border-radius:6px;"></div>