controlling graphic displayed size in XSL

I am running xml version 1.0 on an AIX FOP engine.

I have tried many of the suggestions listed in the archives but not had  a
successful outcome.  I need to be able to control the size of the image
being displayed.  Is it possible?

Here is what is currently in place.

<fo:block-container overflow="hidden" display-align="before"
content-height="scale-to-fit" height="2.00in"
content-width="scale-to-fit" width="2.00in" scaling="non-uniform">
      <fo:block>
              <xsl:element name="fo:external-graphic" >
                      <xsl:attribute name="src">file:<xsl:value-of
select="/data/rmHeaderImage"/></xsl:attribute>
                </xsl:element>
      </fo:block>
</fo:block-container>

Any help would be greatly appreciated.