From: sender@example.invalid
To: recipient@example.invalid
Subject: Unreferenced related inline image
Date: Tue, 01 Oct 1996 10:00:00 -0400
Message-ID: <unreferenced-related-inline-image@example.invalid>
Content-Type: multipart/related;
	boundary="_004_related_boundary_";
	type="multipart/alternative"
MIME-Version: 1.0

--_004_related_boundary_
Content-Type: multipart/alternative;
	boundary="_000_alternative_boundary_"

--_000_alternative_boundary_
Content-Type: text/plain; charset="Windows-1252"
Content-Transfer-Encoding: quoted-printable

Test body content.

--_004_related_boundary_
Content-Type: image/png; name="sample.png"
Content-Description: sample.png
Content-Disposition: inline; filename="sample.png"
Content-ID: <unreferenced-image-cid@example.invalid>
Content-Transfer-Encoding: base64

iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAAAAAA6fptVAAAACklEQVR42mMAAQAABQABDQottAAAAABJRU5ErkJggg==

--_004_related_boundary_--