EML files
In OS X Lion, Apple has decided to drop support for exporting RTFD (i.e. RTF files with pictures embedded) from Mail. So if you want to export an e-mail with images, the only option is the newly added “raw message format”, which will give you an EML file. But what to do with this file? According to Wikipedia, .eml files are: plain text in MIME format, containing the email header as well as the message contents and attachments in one or more of several formats. ...