I'm trying to send an e-mail to a contact list that will have one central image in the body. I'm working on a mac and was wondering if it would be good to do this with HTML (if so how?) or if it is possible to just send as a jpeg in the text. I use Yahoo mail and Microsoft Entourage for sending and receiving.

Set your Yahoo email to enable HTML and add your image into the body if you can do that (I don't use Yahoo mail) but yes you will need to do this using HTML email to get the image into the body of the mail when your recipients view your message.

Keep in mind some recipients have HTML disabled for speed as well as for security so they won't get to see your image formatted email but will get to see your text.