continuum-docs/src/site/resources/pdf-config.xml

<xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform" xmlns:fo="http://www.w3.org/1999/XSL/Format" version="1.0">

    <xsl:attribute-set name="figure.graphics">
        <xsl:attribute name="height">100%</xsl:attribute>
        <xsl:attribute name="width">100%</xsl:attribute>
        <xsl:attribute name="content-height">scale-down-to-fit</xsl:attribute>
        <xsl:attribute name="content-width">scale-down-to-fit</xsl:attribute>
    </xsl:attribute-set>

</xsl:stylesheet>