code: def post_process_images(self, doctree):
          
  
          super(AbstractSlideBuilder, self).post_process_images(doctree)
  
          # figure out where this doctree is in relation to the srcdir
          relative_base = (
              ['..'] *
              doctree.attributes.get('source')[len(self.srcdir) + 1:].count('/')
          )
  
          for node in doctree.traverse(nodes.image):
  
              if node.get('candidates') is None:
                  node['candidates'] = ('*',)
  
              # fix up images with absolute paths
              if node['uri'].startswith(self.outdir):
                  node['uri'] = '/'.join(
                      relative_base + [
                          node['uri'][len(self.outdir) + 1:]
                      ]
                  )
docs: Pick the best candidate for all image URIs.