Mime message example (smtp telnet DATA example):
From: from@ccc.cc
To: to@@ccc.cc
Subject: Example Email
MIME-Version: 1.0
Content-Type: multipart/mixed; boundary="MixedBoundaryString"
--MixedBoundaryString
Content-Type: multipart/related; boundary="RelatedBoundaryString"
--RelatedBoundaryString
Content-Type: multipart/alternative; boundary="AlternativeBoundaryString"
--AlternativeBoundaryString
Content-Type: text/plain;charset="utf-8"
Content-Transfer-Encoding: quoted-printable
This is the plain text part of the email.
--AlternativeBoundaryString
Content-Type: text/html;charset="utf-8"
Content-Transfer-Encoding: quoted-printable
<html>
<body>=0D
<img src=3D=22cid:masthead.png=40ccc.cc=22 width 800 height=3D80=
=5C>=0D
<p>This is the html part of the email.</p>=0D
<img src=3D=22cid:logo.png=40ccc.cc=22 width 200 height=3D60 =5C=
>=0D
</body>=0D
</html>=0D
--AlternativeBoundaryString--
--RelatedBoundaryString
Content-Type: image/jpgeg;name="logo.png"
Content-Transfer-Encoding: base64
Content-Disposition: inline;filename="logo.png"
Content-ID: <logo.png@ccc.cc>
amtsb2hiaXVvbHJueXZzNXQ2XHVmdGd5d2VoYmFmaGpremxidTh2b2hydHVqd
dWkgb2l1b3NydGhpdXRvZ2hqdWlyb2h5dWd0aXJlaHN1aWhndXNpaHhidnVqZ
a25qbW9nNXRwbF0nemVycHpvemlnc3k5aDZqcm9wdHo7amlodDhpOTA4N3U5
LGZ2cDBbZWRzcm85eWo1Zmtsc2xrZ3g=
--RelatedBoundaryString
Content-Type: image/jpgeg;name="masthead.png"
Content-Transfer-Encoding: base64
Content-Disposition: inline;filename="masthead.png"
Content-ID: <masthead.png@ccc.cc>
aXR4ZGh5Yjd1OHk3MzQ4eXFndzhpYW9wO2tibHB6c2tqOTgwNXE0aW9qYWJ6aX
dGlmOTA0cW05dGkwbWk0OXQwYVttaXZvcnBhXGtsbGo7emt2c2pkZnI7Z2lwb2F
eXN6dWdoeXhiNzhuZzdnaHQ3eW9zemlqb2FqZWt0cmZ1eXZnamhka3JmdDg3aXV2dWd5aGVidXdz
dhyuhehe76YTGSFGA=
--RelatedBoundaryString--
--MixedBoundaryString
Content-Type: application/pdf;name="Invoice_1.pdf"
Content-Transfer-Encoding: base64
Content-Disposition: attachment;filename="Invoice_1.pdf"
aGZqZGtsZ3poZHVpeWZoemd2dXNoamRibngganZodWpyYWRuIHVqO0hmSjtyRVVPIEZSO05SVURF
SEx1aWhudWpoZ3h1XGh1c2loZWRma25kamlsXHpodXZpZmhkcnVsaGpnZmtsaG
a2psajY1ZWxqanNveHV5ZXJ3NTQzYXRnZnJhZXdhcmV0eXRia2xhanNueXVpNjRv
--MixedBoundaryString
Content-Type: application/pdf;name="SpecialOffer.pdf"
Content-Transfer-Encoding: base64
Content-Disposition: attachment;filename="SpecialOffer.pdf"
aXBvY21odWl0dnI1dWk4OXdzNHU5NTgwcDN3YTt1OTQwc3U4NTk1dTg0dTV5OG
cS0zNHU4NTk0eWI4OTcwdjg5MHE4cHV0O3BvYTt6dWI7dWlvenZ1em9pdW51dD
OTViOHk5cDV3dTh5bnB3dWZ2OHQ5dTh2cHVpO2p2Ymd1eTg5MGg3ajY4bjZ2ODl1ZGlvcjQ1amts
dfnhgjdfihn=
--MixedBoundaryString--
.
// Or you can download from
https://www.phpclasses.org/browse/file/14672.html