2.1.3.4 Attachments

Each Attachment object in a Message object represents one attachment. MIME writers SHOULD classify Attachment objects based on the value of the PidTagAttachMethod property ([MS-OXCMSG] section 2.2.2.9), as specified in the following table.

PidTagAttachMethod property value

Attachment object classification

5

Embedded Message object attachments

6

OLE attachments

All other values

Ordinary file attachments

Note that ordinary file attachments can contain additional Macintosh-specific data. These attachments require special handling, as specified in section 2.1.3.4.3.

MIME writers SHOULD generate a vCard 3.0 attachment when generating contact information in a MIME message, as specified in section 2.1.3.4.6.

Additionally, MIME writers SHOULD classify Attachment objects as inline or not inline, as specified in section 2.1.3.4.1.

MIME writers SHOULD generate different MIME structures for the message depending on the presence of inline and non-inline attachments, as specified in the following three examples:

If both inline and non-inline attachments are present, MIME writers SHOULD generate the structure shown in the following figure. For an example of this structure, see section 3.1.2.

Inline and non-inline attachments present

Figure 1: Inline and non-inline attachments present

If only inline attachments are present, MIME writers SHOULD generate the structure shown in the following figure. For an example of this structure, see section 3.1.3.

Only inline attachments present

Figure 2: Only inline attachments present

If only non-inline attachments are present, MIME writers SHOULD generate the structure shown in the following figure. For an example of this structure, see section 3.1.4.

Only non-inline attachments present

Figure 3: Only non-inline attachments present