Message Transmission Optimization Mechanism (MTOM)
Regardless of the flexibility, interoperability, and global acceptance of XML, there are times when serializing data into XML just does not make sense. Web services users may want to transmit binary attachments of various sorts such as images, drawings, XML documents, and so on. together with a SOAP message. Such data is often originally available in a particular binary format.
There are two traditional approaches to dealing with the sending of binary data in XML.
Sending binary data by value is achieved by embedding opaque data (after some form of encoding has taken place of course) as an element or an attribute content of the XML component of data. The main advantage of this technique ...