<?
$img_name =    $_GET['pic'];
$max_width    = $_GET['wd']; // maximum x aperture  in pixels

$max_height   = $_GET['ht']; // maximum y aperture in pixels

/* Returns an array with 4 elements. 
Index 0 contains the width of the image in pixels. 
Index 1 contains the height. 
Index 2 is a flag indicating the type of the image: 1 = GIF, 2 = JPG, 3 = PNG, 4 = SWF, 5 = PSD, 6 = BMP,
 7 = TIFF(intel byte order), 8 = TIFF(motorola byte order), 9 = JPC, 10 = JP2, 11 = JPX, 12 = JB2, 13 = SWC,
  14 = IFF, 15 = WBMP, 16 = XBM. 
  These values correspond to the IMAGETYPE constants that were added in PHP 4.3.0. 
  Index 3 is a text string with the correct height="yyy" width="xxx" string that can be used directly in an IMG tag.
  */
$size= getimagesize($img_name);
$width_ratio  = ($size[0] / $max_width);
$height_ratio = ($size[1] / $max_height);
$type = $size[2];
if($width_ratio >=$height_ratio) 
{
   $ratio = $width_ratio;
}
else
{
   $ratio = $height_ratio;
}
 
$new_width    = ($size[0] / $ratio);
$new_height   = ($size[1] / $ratio);

if ($type==1)
{
header("Content-Type: image/gif");
$src_img = imagecreatefromgif($img_name);
}

if ($type==2)
{
header("Content-Type: image/jpeg");
$src_img = imagecreatefromjpeg($img_name);
}
if ($type==3)
{
header("Content-Type: image/png");
$src_img = imagecreatefrompng($img_name);
}

// Create a new image from file or URL
//imagecreatetruecolor() returns an image identifier representing a black image of size x_size  by y_size.
$thumb = imagecreatetruecolor($new_width,$new_height);
/*imagecopyresampled() copies a rectangular portion of one image to another image,
 smoothly interpolating pixel values so that, in particular,
  reducing the size of an image still retains a great deal of clarity.
  */
imagecopyresampled($thumb, $src_img, 0,0,0,0,($new_width-1),($new_height-1),$size[0],$size[1]);
//Output image to browser or file
if ($type == 1)imagegif($thumb);
if ($type == 2)imagejpeg($thumb);
if ($type == 3)imagepng($thumb);


imagedestroy($src_img);
imagedestroy($thumb);
?>