Worst of all, it is often completely illegible by other email programs. It just sucks. Attachments are equally infuriating. If I am reading my email, that means that I am online. If I am online, it is far easier for me to visit your Web page than it is for me to find and open your attachments.
Attachments live lonely lives.
Photos in particular are the most hateful attachment of all. There is one thing you should include in a PR email, however. Fourth, don't call me. Your job is to tell the world about your exciting company. Meanwhile, I am hard at work myself, and my work almost inevitably has nothing to do with your exciting company.