Email problems with sending attachments

I am having a problem with Outlook Express v6.0 in Windows XP Home Edition. End users at the receiving end of my emails cannot receive .jpg photo attachments. I have downloaded current updates to Windows XP, Internet Explorer and Outlook Express. I’ve had this problem for over a month, especially after I performed many of these updates. Is there one or several updates which might have caused my problem. If so, which one should I uninstall?