I am trying to get a listing of child node folders from a specific media id, which is chosen in with the media picker. The folder structure is as follows:

Media
 - Departments
     - Department A
         - Photo Group 1
- photo 1, photo 2, etc...
 - Photo Group 2
- photo 1, photo 2, etc...

In the media picker I have Department A selected and with the code below, it will only display images that are in that folder directly. I cant seem to figure out how to retrieve the photos in the children folders/nodes. I have tried using $currentPage/DepartmentGallery/*[@isDoc], but that does not seem to return anything

<xsl:variable name="imageRoot" select="$currentPage/DepartmentGallery"/>
  <xsl:if test="string-length($imageRoot) &gt; 0">
    <xsl:for-each select="umbraco.library:GetMedia($imageRoot, '0')/Image">
      <img src="{umbracoFile}" width="100"/>
    </xsl:for-each>
  </xsl:if>

Thanks for the help!