Finally, when I send the attachment the page source gives the
<P><A HREF="bin00000.bin" > nasa2.gif</A></P>
Does this offer any clues?
That's MHonArc output. What's needed for diagnosis is a snippet of what
Eudora (and Pine) is sending, i.e. what MHonarc starts from.
The output does offer a clue, in that to show the image embedded in the
message the MHonArc output would have to read:
<A HREF="bin00000.bin" > nasa2.gif</A>
which gives a clickable link.