How do you "copy and paste" a JPEG screen shot in an email?

It depends on what email client you're using. The email protocol is 7-bit, which means any extended character sets or graphics have to be encoded first with something like MIME or UUencode. Most email clients will do that for you automagically. Look for an "attachments" tab or radio button on your email client when you set up a new email document which will allow you to select your graphics file as an attachment or enclosure.