figure in html looks different then the same in pdf

[Melanie Rösch <m.roesch@rose.de>]

I want to convert my docbook-document to different output formats.
The html output looks very pretty, but if I generate pdf, then it seems
that figures will be scaled bigger.

I include my figures with the following way:

  <figure id="fig_intorductoryExample"><title>The Introductory 
Example</title>
    <mediaobject>
      <imageobject>
        <imagedata fileref="rodelicaFigures/smallCircuit.gif" format="GIF"/>
      </imageobject>
    </mediaobject>
  </figure> 

What is wrong?

Regards
Melanie Rösch