Image Type BMP @ "Save Image As" Dialog on IE

I have wrote a PHP script that serves JPEG images in smaller size, the resize is done using GD on-the-fly. I have noticed an interesting issue during the "save image as..." dialog on serveral internet explorer browsers, somehow, for some strange reason, the JPEG file is shown as BMP file. I don't know why this is happening, but I'm trying to make it save it as JPG file. In firefox or any other browser everything works like a charm. I have to mention that the JPG file is located in the HTML in the following format: <img src='xxx.jpg' alt='aaa' style='border:0;' /> I have also used mod_rewrite to serve the file with .jpg extension (I thought that the strange IE may not know how to recognize it..), the PHP file is sending the correct headers, I'm attaching an example for HTTP request & response for this resized image: GET /gallery-image-dolphinim-12450163853. HTTP/1.1 Host: www.dolphinim.net User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.9.0.10) Gecko/2009042316 Firefox/3.0.10 FirePHP/0.3 Accept: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8 Accept-Language: en-us,en;q=0.5 Accept-Encoding: gzip,deflate Accept-Charset: ISO-8859-1,utf-8;q=0.7,*;q=0.7 Keep-Alive: 300 Connection: keep-alive Cookie: PHPSESSID=e4542edfa5bcb7904e351d39c341fffa HTTP/1.x 200 OK Date: Fri, 26 Jun 2009 16:18:52 GMT Server: Apache/1.3.41 (Unix) PHP/5.2.6 mod_log_bytes/1.2 mod_bwlimited/1.4 mod_auth_passthrough/1.8 FrontPage/5.0.2.2635 DAV/1.0.3 mod_ssl/2.8.31 OpenSSL/0.9.8e-fips-rhel5 X-Powered-By: PHP/5.2.6 Expires: Thu, 19 Nov 1981 08:52:00 GMT Cache-Control: no-store, no-cache, must-revalidate, post-check=0, pre-check=0 Pragma: no-cache Keep-Alive: timeout=15, max=98 Connection: Keep-Alive Transfer-Encoding: chunked Content-Type: image/jpeg Any directions will be highly appreciated! Thanks!