PHPImageResize

  // scale src image to fit given w / h
  $sw = imagesx($src);
  $sh = imagesy($src);

  // try "fit width" ($nw = $tw)
  $center = true;
  $sdx = 0; $sdy = 0;
  $nw = $w;
  $nh = round($sh * ($nw / $sw));
  if ($nh < $h) {
    // if height is to small "fit height"
    $nh = $h;
    $nw = round($sw * ($nh / $sh));
    if ($center) { $sdx = round(($nw - $w) / 2); }
  } else {
    if ($center) { $sdy = round(($nh - $h) / 2); }
  }
  // scale image
  $scaledimage = imagecreatetruecolor($nw, $nh);
  imagecopyresampled($scaledimage, $src, 0, 0, 0, 0, $nw, $nh, $sw, $sh);