resize('alucard.jpg', 100, 'alucard_0.jpg');

$mem_after = memory_get_peak_usage();//this function avaliable in PHP 5.2+
$time_end = microtime(true);
$time = $time_end - $time_start;
print '

	before
	after

//Get Image size info
$imgInfo = getimagesize($img);
$format = ereg_replace(".*\.(.*)$","\\1",$img);
$format = strtolower($format);

switch ($format) {
case "gif": $im = imagecreatefromgif($img); break;
case "jpg":
case "jpeg": $im = imagecreatefromjpeg($img); break;
case "png": $im = imagecreatefrompng($img); break;
default: trigger_error('Unsupported filetype!', E_USER_WARNING); break;
}
//calculate size
if($imgInfo[0]>=$imgInfo[1]){
$nWidth = $w;
$nHeight = ($nWidth/$imgInfo[0])*$imgInfo[1];
}else{
$nHeight = $w;
$nWidth = ($nHeight/$imgInfo[1])*$imgInfo[0];
}
$nWidth = round($nWidth);
$nHeight = round($nHeight);
$newImg = imagecreatetruecolor($nWidth, $nHeight);

// Check if this image is PNG or GIF, then set if Transparent
if(($imgInfo[2]==3)){
imagealphablending($newImg, false);
imagesavealpha($newImg,true);
$transparent = imagecolortransparent($im);
imagefilledrectangle($newImg, 0, 0, $nWidth, $nHeight, $transparent);
}elseif(($imgInfo[2] == 1)){
imagetruecolortopalette($newImg, false, 255);
$idx = imagecolortransparent($im);
$rgba = imagecolorsforindex($im,idx);
$transparent = imagecolorallocatealpha($newImg, $rgba['red'], $rgba['green'], $rgba['blue'],$rgba['alpha']);
imagecolortransparent($newImg, $transparent);
imagefilledrectangle($newImg, 0, 0, $nWidth, $nHeight, $transparent);
}
imagecopyresampled($newImg, $im, 0, 0, 0, 0, $nWidth, $nHeight, $imgInfo[0], $imgInfo[1]);

//Generate the file, and rename it to $newfilename
switch ($imgInfo[2]) {
case 1: imagegif($newImg,$newfilename); break;
case 2: imagejpeg($newImg,$newfilename); break;
case 3: imagepng($newImg,$newfilename); break;
default: trigger_error('Failed resize image!', E_USER_WARNING); break;
}
imagedestroy($im);
return $newfilename;
}
$time_start = microtime(true);
$mem_before = memory_get_usage();//this function avaliable in PHP 5.2+

resize('alucard.jpg', 100, 'alucard_1.jpg');

$mem_after = memory_get_peak_usage();//this function avaliable in PHP 5.2+
$time_end = microtime(true);
$time = $time_end - $time_start;
print '

	before
	after