code: def renderThumbnail(self, relpath=""):
          
          # no thumbnail -- return empty string
          if self.thumbnail is None:
              return ""
          # else thumbnail is same as full image (because image was small enough), insert directly
          elif self.thumbnail is self.fullimage:
              fname = relpath + self.fullimage
              return """<IMG SRC="%s" ALT="%s"></IMG>""" % (quote_url(fname), quote_url(os.path.basename(self.filename)))
          # else return thumbnail linking to full image
          else:
              tname = relpath + self.thumbnail
              fname = relpath + self.fullimage
              return """<A HREF="%s"><IMG SRC="%s" ALT="%s"></A>""" % (
              quote_url(fname), quote_url(tname), quote_url(os.path.basename(self.filename)))
docs: renderThumbnail() is called to render a thumbnail of the DP (e.g. in Data Product tables).