Need to change the graphic in cautions

["McKinstry, Scott A" <scott.a.mckinstry@lmco.com>]

I am composing to html using Docbook xsl stylesheets.

I have included the admon.graphics parameter in my custom layer.
<xsl:param name="admon.graphics" select="1"></xsl:param> 
This inserts <img alt="[Caution]" src="images/caution.png"/>
into my output code.

I need to change 'images/caution.png' but can not find the Stylesheet controls this.
What is the Stylesheet that puts this line into my output file?

Thanks