I'm trying to display a thumbnail image on my parent node of an image I've uploaded to my grandchild node. But so far haven't had any success.
The alias for the uploaded image is "projectImage" but I'm not sure of the correct code needed to display the thumbnail.
Can anyone help?

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE xsl:stylesheet [ <!ENTITY nbsp "&#x00A0;"> ]>
<xsl:stylesheet 
  version="1.0" 
  xmlns:xsl="http://www.w3.org/1999/XSL/Transform" 
  xmlns:msxml="urn:schemas-microsoft-com:xslt" 
  xmlns:umbraco.library="urn:umbraco.library" xmlns:Exslt.ExsltCommon="urn:Exslt.ExsltCommon" xmlns:Exslt.ExsltDatesAndTimes="urn:Exslt.ExsltDatesAndTimes" xmlns:Exslt.ExsltMath="urn:Exslt.ExsltMath" xmlns:Exslt.ExsltRegularExpressions="urn:Exslt.ExsltRegularExpressions" xmlns:Exslt.ExsltStrings="urn:Exslt.ExsltStrings" xmlns:Exslt.ExsltSets="urn:Exslt.ExsltSets" 
  exclude-result-prefixes="msxml
 umbraco.library Exslt.ExsltCommon Exslt.ExsltDatesAndTimes 
Exslt.ExsltMath Exslt.ExsltRegularExpressions Exslt.ExsltStrings 
Exslt.ExsltSets ">

<xsl:output method="xml" omit-xml-declaration="yes"/>

<xsl:param name="currentPage"/>

<xsl:template match="/">
<xsl:value-of select="umbraco.library:RegisterStyleSheetFile('slider1', '/css/project_gallery.css')"/>
  <div id="project_gallery">
<!-- The fun starts here -->
<xsl:for-each select="$currentPage/* [@isDoc and string(umbracoNaviHide) != '1']">
<div id="project">

<!-- get first photo thumbnail -->
    <a href="{umbraco.library:NiceUrl(@id)}">
      <xsl:if test="count(./* [@isDoc]) &gt; 0">
        <img src="{concat(substring-before(./*/umbracoFile,'.'), '_thumb.jpg')}" style="border: none;"/>
      </xsl:if>
      
      <xsl:if test="$currentPage/child::node/projectImage != ''">
        <img alt="">
        <xsl:attribute name="src">
          <xsl:value-of select="$currentPage/child::node/projectImage" />
        </xsl:attribute>   
      </img>
      </xsl:if>
      
      <xsl:if test="completionDate != ''">
        <h1><xsl:value-of select="umbraco.library:FormatDateTime(completionDate, 'MMMM yyyy')"/></h1>
      </xsl:if>
      <xsl:if test="projectClient != ''">
        <h2><xsl:value-of select="projectClient" /></h2>
      </xsl:if>
      <xsl:if test="projectLocation != ''">
        <p><xsl:value-of select="projectLocation" /></p>
      </xsl:if>
    </a>
</div>

</xsl:for-each>
    </div>
</xsl:template>

</xsl:stylesheet>