Gazelle/image.php

<?
// Functions and headers needed by the image proxy
error_reporting(E_COMPILE_ERROR|E_RECOVERABLE_ERROR|E_ERROR|E_CORE_ERROR);

if (isset($_SERVER['HTTP_IF_MODIFIED_SINCE'])) {
  header("HTTP/1.1 304 Not Modified");
  die();
}

header('Expires: '.date('D, d-M-Y H:i:s \U\T\C', time() + 3600 * 24 * 120)); // 120 days
header('Last-Modified: '.date('D, d-M-Y H:i:s \U\T\C', time()));

if (!extension_loaded('gd')) {
  error('nogd');
}

function img_error($Type) {
  header('Content-type: image/gif');
  die(file_get_contents(SERVER_ROOT.'/sections/image/'.$Type.'.gif'));
}

function invisible($Image) {
  $Count = imagecolorstotal($Image);
  if ($Count == 0) {
    return false;
  }
  $TotalAlpha = 0;
  for ($i = 0; $i < $Count; ++$i) {
    $Color = imagecolorsforindex($Image, $i);
    $TotalAlpha += $Color['alpha'];
  }
  return (($TotalAlpha / $Count) == 127);

}

function verysmall($Image) {
  return ((imagesx($Image) * imagesy($Image)) < 25);
}

function image_type($Data) {
  if (!strncmp($Data, 'GIF', 3)) {
    return 'gif';
  }
  if (!strncmp($Data, pack('H*', '89504E47'), 4)) {
    return 'png';
  }
  if (!strncmp($Data, pack('H*', 'FFD8'), 2)) {
    return 'jpeg';
  }
  if (!strncmp($Data, 'BM', 2)) {
    return 'bmp';
  }
  if (!strncmp($Data, 'II', 2) || !strncmp($Data, 'MM', 2)) {
    return 'tiff';
  }
  if (!substr_compare($Data, 'webm', 31, 4)) {
    return 'webm';
  }
}

function image_height($Type, $Data) {
  $Length = strlen($Data);
  global $URL, $_GET;
  switch ($Type) {
    case 'jpeg':
      // See http://www.obrador.com/essentialjpeg/headerinfo.htm
      $i = 4;
      $Data = (substr($Data, $i));
      $Block = unpack('nLength', $Data);
      $Data = substr($Data, $Block['Length']);
      $i += $Block['Length'];
      $Str []= "Started 4, + ".$Block['Length'];
      while ($Data != '') { // iterate through the blocks until we find the start of frame marker (FFC0)
        $Block = unpack('CBlock/CType/nLength', $Data); // Get info about the block
        if ($Block['Block'] != '255') { // We should be at the start of a new block
          break;
        }
        if ($Block['Type'] != '192') { // C0
          $Data = substr($Data, $Block['Length'] + 2); // Next block
          $Str []= "Started $i, + ".($Block['Length'] + 2);
          $i += ($Block['Length'] + 2);
        } else { // We're at the FFC0 block
          $Data = substr($Data, 5); // Skip FF C0 Length(2) precision(1)
          $i += 5;
          $Height = unpack('nHeight', $Data);
          return $Height['Height'];
        }
      }
      break;
    case 'gif':
      $Data = substr($Data, 8);
      $Height = unpack('vHeight', $Data);
      return $Height['Height'];
    case 'png':
      $Data = substr($Data, 20);
      $Height = unpack('NHeight', $Data);
      return $Height['Height'];
    default:
      return 0;
  }
}

define('SKIP_NO_CACHE_HEADERS', 1);
require('classes/script_start.php'); // script_start contains all we need and includes sections/image/index.php
?>