[pdftex] simple graphics question

[Steven E. Landsburg]

I am writing plain TeX (*not* LaTeX) and want to be able to
produce both .dvi and .pdf files from the same source.  I
have no problem doing this as long as there are no graphics
involved.

Now I'm trying to make the graphics work.

What I've done:

   My document contains the lines

     \input eplain
     \input epsf
     \input graphicx
     \includegraphics[bb=100 100 200 200]{bigjug.jpg}

What happens:

    pdftex gets to the \includegraphics line and says "non-PDF special
    ignored", then creates a .pdf file that fails to include the 
    picture.

I'm sure there's something very basic that I'm missing here.  Can 
someone tell me what it is?

Steven E. Landsburg
steven at landsburg.com