Without identifying the email program you are using, there is no possibility except pure luck that anyone will guess what it is and provide a relevant answer. It must not be Outlook, because you can generally right-click an attachment and choose "Print."
If all else fails, take a screen shot by pressing the Print screen button (usually located right of the F1-12 keys) and paste it into paint then crop it in paint and then print it from there. the quality probably wont be amazing but it works as a last resort =p
Oh, CTRL+ALT+PRINTSCREEN takes a screenshot of only the program you have open ( minimizes editing )