[ci skip] Fix class reference sections of Image_lib, Parser and User agent docs
diff --git a/user_guide_src/source/libraries/image_lib.rst b/user_guide_src/source/libraries/image_lib.rst
index cde4e44..cf23e39 100644
--- a/user_guide_src/source/libraries/image_lib.rst
+++ b/user_guide_src/source/libraries/image_lib.rst
@@ -19,6 +19,13 @@
order for the script to calculate the image properties. The image
processing, however, will be performed with the library you specify.
+.. contents::
+ :local:
+
+.. raw:: html
+
+ <div class="custom-index container"></div>
+
**********************
Initializing the Class
**********************