An attachment is part of the message as recieved by Mercury and will be part of the message file (.CNM file) in the mailbox directory. One file can contain a number of different MIME parts. It's up to your email client to handle the attachment in a sensible way when you collect your mail from Mercury.

/Rolf  

How do the attachments in Mercury32 work? by this I mean if you open the a message I cant see a reference to the attachment, where are the attachments stored? I tried looking in the help about attachments but it mainly mentions filtering. I know you can add filtering rules to save the attachments but other than this I don't know much about the attachments and cant seem to find any resources on how Mercury32 deals with them.