Thanks, chaika. An attachment or a link will be my last resort, I'd like to make it visible in the email's body.
I uploaded the file to imageshack.us (it's only 200 kb so no problem here), and tried to use an "embedding" link (an html code). But for some reason I could not make it work when I copy-pasted it into email's body. It turns into text. How can I make gmail see it as html? ^_^