code: def is_valid_filename(self, image_node):
          
          src = self.parser.getAttribute(image_node, attr='src')
  
          if not src:
              return False
  
          if self.badimages_names_re.search(src):
              return False
  
          return True
docs: \
          will check the image src against a list
          of bad image files we know of like buttons, etc...