makeThumb.class.php
<?

class thumbMaker{

	var $extension;

	var $upfile;

	var $dstfile;

	function makeThumb($max_width, $max_height, $upfile, $dstfile){

		  

		   $size = GetImageSize($upfile);

		         $width = $size[0];

		         $height = $size[1];

		        

		         $x_ratio = $max_width / $width;

		         $y_ratio = $max_height / $height;



		         if( ($width <= $max_width) && ($height <= $max_height) )

		         {

		               $tn_width = $width;

		               $tn_height = $height;

		         }

		         elseif (($x_ratio * $height) < $max_height)

		         {

		               $tn_height = ceil($x_ratio * $height);

		               $tn_width = $max_width;

		         }

		         else

		         {

		               $tn_width = ceil($y_ratio * $width);

		               $tn_height = $max_height;

		         }

			 if ($this->extension == "jpg"){

			     $src = ImageCreateFromJpeg($upfile);

			     $dst = ImageCreateTrueColor($tn_width, $tn_height);

			     ImageCopyResized($dst, $src, 0, 0, 0, 0, $tn_width, $tn_height, $width, $height);

			     ImageJpeg($dst, $dstfile);

			 } else {

				 $src = ImageCreateFromGif($upfile);

			     $dst = ImageCreateTrueColor($tn_width, $tn_height);

			     ImageCopyResized($dst, $src, 0, 0, 0, 0, $tn_width, $tn_height, $width, $height);

			     ImageGif($dst, $dstfile);

			 }

	}

}

?>






example.php



<?

// Simple thumbnail maker

// Variables available are

// extension, upfile, dstfile, max_width, max_height

// Currently supports GIF and JPG

// makeThumb($max_width, $max_height, $upfile, $dstfile);

include('makeThumb.class.php');
$tum = new thumbMaker;

$grabExt = explode(".", $_FILES['file']['name']);

$tum->extension = $grabExt[1];

$tum->upfile = $_FILES['file']['tmp_name'];

$tum->dstfile = "mythumb/" . $_FILES['file']['name'];

$tum->makeThumb(100,100);

?>