def to_thumb(c)
      current = self.__send__(c)
      if model.respond_to?(:stash_reflection) && model.stash_reflection.key?(c)
        !current.nil? && current[:type][/^image\//] ? "<img src='#{file_url(c, 'stash_thumb.gif')}?#{::Time.now.to_i.to_s}' /><br />\n" : ''
      else
        "<img src='#{current}?#{::Time.now.to_i.to_s}' width='100' onerror=\"this.style.display='none'\" />\n"
      end
    end
def to_thumb(c)
      current = self.__send__(c)
      if model.respond_to?(:stash_reflection) && model.stash_reflection.key?(c)
        !current.nil? && current[:type][/^image\//] ? "<img src='#{file_url(c, 'stash_thumb.gif')}?#{::Time.now.to_i.to_s}' /><br />\n" : ''
      else
        "<img src='#{current}?#{::Time.now.to_i.to_s}' width='100' onerror=\"this.style.display='none'\" />\n"
      end
    end
Provide a thumbnail for the column