DOCBOOK: images (cont'd)

Hello,

I do get images in my article. However, for some unknown (:)) reason it
does try to enlarge images. The enlarged copies look really bad. How can I
force DSSSL stylesheet not to do any image processing just to put as it
is?

I use something like this in article.xml file

<!ENTITY simplearchitecture SYSTEM "simplearchitecture.png" NDATA PNG>

.....

  <figure id="fig02"><title>Target architecture</title>
      <mediaobject>
	<imageobject><imagedata entityref="simplearchitecture"/>
	</imageobject>
      </mediaobject>
    </figure>

regards,
Radek