code: def get_template_context(src, container="div", classes="", inner_classes="", alt="", background_image=False, no_css=False, aria_hidden=False):
      
      context = {
          "container": container,
          "classes": classes,
          "aspect_padding_bottom": aspect_ratio_percent(src),
          "alt": alt,
          "background_image": background_image,
          "no_css": no_css,
          "inner_classes": inner_classes,
          "aria_hidden": aria_hidden,
      }
  
      # We can't do any of the srcset (or JS switching fallback) if we don't
      # have a thumbnail library installed.
      if not get_thumbnail_engine():
          context["image"] = src
          return context
  
      sizes = get_image_sizes(src)
      context["image_sizes"] = sizes
  
      # Set the first image in the list as the one to be rendered initially
      # (pre-JS-fallback). `if sizes` might not be a necessary check...
      context["image"] = sizes[0]
  
      context["image_sizes_json"] = json.dumps(sizes)
      srcset_items = ["{} {}w".format(size["url"], size["width"]) for size in sizes]
  
      context["image_sizes_srcset"] = ", ".join(srcset_items)
      return context
docs: Returns a template context for a flexible image template
      tag implementation.