[Dvipng] transparent PNGs via \includegraphics ?

[jw]

Hello,

I have a transparent image that I want to insert into my document, and
I was hoping that dvipng would preserve that transparency in the final
output.
Is that possible?

Using the "-bg Transparent" option for dvipng makes all the "white
space" on the page transparent, but the inserted graphic still is not.
The inserted bitmap looks as if it were placed over a black background.

I can provide a simple example if needed.

-John