imap_body() returns the body of the message, numbered msg_number in the current mailbox. The optional flags are a bit mask with one or more of the following:
FT_UID - The msgno is a UID
FT_PEEK - Do not set the \Seen flag if not already set
FT_INTERNAL - The return string is in internal format, will not canonicalize to CRLF.
imap_body() will only return a verbatim copy of the message body. To extract single parts of a multipart MIME-encoded message you have to use imap_fetch_structure() to analyze its structure and imap_fetch_body() to extract a copy of a single body component.