Helping people with computers... one answer at a time.
Attachments are a source of great confusion for many people. In concept they're very, very simple. Excruciatingly simple, as a matter of fact.
Then some email programs try to get "helpful", and all heck breaks loose.
Attachments are nothing more than files that accompany an email message. There's nothing special about them, there's nothing magical. It's just a file. Save it to disk, and you can do anything you want with that file, assuming you have the proper tools on your machine to act on it.
Some email programs try to get fancy when they display an email message that has accompanying attachments. Outlook Express, for example, will notice if the attachments appear to be images, and if they are, it will helpfully display those images below the email message body. The problem is that while it looks like the images are below the message, in fact they are not. That very same message viewed in a different email program (say, Microsoft Office's Outlook) will not display the images below the body. Outlook will only display the icons that indicate that the message has attachments. If you want to open them, you'll need to do so explicitly.
It's a source of frustration and confusion for people moving from Outlook Express to Outlook, because they find Outlook Express's behavior convenient.
It's also a source of frustration for people attempting to send mail that will look the same everywhere.
HTML mail and Rich Text mail can get even more confusing, because images that appear in-line in one person's mail program may appear as separate attachments to someone else looking at the same message. Or worse ... the entire email message may appear as an attachment.
And so it goes with printing. There's no standard way to print an email message that has attachments. Some programs will print an indicator that there are attachments. Others will not. Some will print the attachment, if they know how, others will print a placeholder or nothing at all.
So in short, there is no blanket answer to what you're looking for. You'll have to experiment with your email program to see if it supports printing email the way you want. Be sure to look for "Page Setup" and advanced printing types of options. Your email program may call them something else, but they hold the keys to what will be possible.