html specials behave weird

Here is an example tex file:

\documentclass{article}
\usepackage{graphicx}
\begin{document}
\special{html:<a href="file:ems1.jpg">}
\includegraphics[width=0.5\textwidth]{ems1}
\special{html:</a>}
\end{document}

Now, there are several problems.

1.
Acoording to the man page and
http://ricardo.ecn.wfu.edu/~cottrell/xdvi/ , xdvi should
start the external viewer as specified in ~/.mailcap.
However, it starts the one I have specified in the X
resource XDvi.wwwBrowser.

2.
If I replace the file 'ems1.jpg' with 'ems.qqq' in the
special command, then xdvi does not start an external
viewer at all. There is no error message either.
According to the man page, it should start the browser
specified in the X resource (or the command line).
The difference between 'ems1.qqq' and 'ems1.jpg' is
that the latter is actually present in a subdirectory,
while the former is not.

In both cases, the link is there in xdvi, and the cursor
changes to a hand when i move the mouse over the
image.

What I would need is to be able to specify an external
link to ems1.qqq, so that I can be sure that xdvi starts
the viewer given in the X resources, and not some
other browser in the ~/.mailcap.

3.
It seems to me that if the image goes beyound the
right border of the page, then xdvi does not hyperlink
it at all. In my case, when I omit "width=0.5\textwidth",
then the image is too large, so it gets clipped at the
right border, but now xdvi does not display a link at all.
This is not such a big deal, because usually I don't
want images to be too large for the page.

Regards,
Gab.