The MIME Content-disposition header provides presentation information for the body-part. It is often added to attachments specifying whether the attachment body part should be displayed (inline) or presented as a file name to be copied (attachment). The Content-disposition header has the following format:
Content-disposition: disposition_type; parameter=value;parameter=value...
disposition_type is usually inline (display the body part) or attachment (present as file to save.) Attachment usually has the parameter filename with a value specifying the suggested name for the saved file.
For details on the Content-disposition header, refer to RFC2183.