Images can just be added as attachments however, they don't have to be inline. Many GUI mailbrowsers can display them as previews. If for some reason they are a

Images can just be added as attachments however, they don't have to be inline. Many GUI mailbrowsers can display them as previews. If for some reason they are absolutely required to be inline of text, its easier on the recipient of the message, if the document is composed as a separate file (pdf or whatever), and sent as attachment.