SOAP (Simple Object Access Protocol) uses xml data for communicate. It can run on top of a Protocols as HTTP. The data exchanged uses the soap xml name space and has the soap:Envelope as root element. Sub elements can be the optional header element and the mandatory body element. Inside the body there is usually an other name space used. This namespace is application specific and defined by the soap user.
As with http, there are usually a request and a response messages involved. There is http post and http get.
SOAP with Attachments (SwA) allows to use mime to attach files as pictures.