This should work for you!
<?$image = "your_image.png";$image_info = getimagesize($image);$width = $image_info[0];$height = $image_info[1];$mime_type = $image_info["mime"];$maxWidth = 250;$maxHeight = 250;$quality = 9;header("Content-type: $mime_type");$canvas = imagecreatetruecolor($maxWidth, $maxHeight);imagealphablending($canvas, false);$background = imagecolorallocatealpha($canvas, 255, 255, 255, 127);imagefilledrectangle($canvas, 0, 0, $maxWidth, $maxHeight, $background);imagealphablending($canvas, true);$leftOffset = ($maxWidth / 2) - ($width / 2);$topOffset = ($maxHeight / 2) - ($height / 2);switch($mime_type){ case "image/jpeg": //JPG code break; case "image/gif": //GIF code break; case "image/png": $new_image = imagecreatefrompng($image); imagecopyresampled($canvas, $new_image, $leftOffset, $topOffset, 0, 0, $width, $height, $width, $height); imagealphablending($canvas, true); imagesavealpha($canvas, true); imagepng($canvas, null, $quality); imagedestroy($canvas); break;}?>