MIME is the Multipurpose Internet Mail Extensions specification. It offers a way to interchange text in languages with different character sets, and multimedia e-mail among many different computer systems that use Internet mail standards. In addition, MIME also permits you to define your own types of message parts.
MIME messages can also contain multiple objects.
When multiple objects are in a MIME message, they are represented in a form called a body part. A body part has a header and a body. Body parts can be nested in bodies that contain one or multiple body parts. The content-type values, subtypes, and parameter names defined in the MIME standard are not case sensitive. The MIME standard is written to allow MIME to be extended in certain ways, without having to revise the standard.