无需黑客。使用cid:URI方案

 --boundary-example 1
 Content-Type: Text/HTML; charset=US-ASCII

 to the other body part, for example through a statement such as:
 <IMG SRC="cid:foo4*foo1@bar.net" ALT="IETF logo">

 --boundary-example-1

 Content-ID: <foo4*foo1@bar.net>
 Content-Type: IMAGE/GIF
 Content-Transfer-Encoding: BASE64

 R0lGODlhGAGgAPEAAP/////ZRaCgoAAAACH+PUNvcHlyaWdodCAoQykgMTk5
 NSBJRVRGLiBVbmF1dGhvcml6ZWQgZHVwbGljYXRpb24gcHJvaGliaXRlZC4A
 etc...

 --boundary-example-1--