Picture downloading in IE

Hi, I have a strange error / misfunction with PHP header and IE7. I render a JPG from a database BLOB to show it on a page. In Firefox, when the user clicks on the image, and selects "Save image as... ", (s)he can download it in JPG format. But when a user in IE7 does the same, (s)he only can getit in BMP. The header I sent is the same both case: header('Content-Type: image/pjpeg'); I tried to set Content-Disposition to "inline" or "attachment", set filename to different values, but get the same result. Now all I can say is "HEEEEEELP" :) Thanks, SanTa