imagejpeg() save as bmp

[Superdog]

Hi Guys,

I am trying to nut this one out. I have a pretty basic dynamic image script

header("Content-type: image/jpeg");

  if($_POST["dept"]=='0'){
  print("Please select a department");
  echo "<br>";
  echo "<a href='logo.html'>Back</a>";
  }
  else{
  $department = $_POST["dept"];	 
  $text = $_POST["logoText"];

  $img = imagecreatefromjpeg("departments/$department");
  $grey = imagecolorallocate($img, 50, 50, 50);
  imageline($img, 0, 0, 0, 100, $grey);

  $white = imagecolorallocate($img, 255, 255, 255);
  $black = imagecolorallocate($img, 0, 0, 0);
  $blue = imagecolorallocate($img, 26, 53, 106);



  imagettftext($img, 12, 0, 8, 65, $blue, "fonts/Geneva.dfont", $text);

	 imagejpeg($img,"", 100);
	 imagedestroy($img);

	 }

Anyways I think I have everything covered. But when I produce the image and right click to save it...
IT SAVES AS A BMP!!!! I was under the impression that if you stipulated the correct header. i.e image/jpeg. Then everything would be fine.
This script saves as a jpg on a mac.

[mattvenables]

could it be your browser settings? in IE the drop down menu allows you to save any jpeg as a bmp, so maybe it is defaulting to a bmp. try right clicking the image and hitting properties, and see if the image is ends with .jpg