diff --git a/README.md b/README.md
index 56e55f1..f707b6d 100644
--- a/README.md
+++ b/README.md
@@ -22,6 +22,8 @@ This plugin creates a bridge between the two, by automatically piping dynamicall
 
 There is no GUI for this plugin, since all it does is that it just hooks on Fly's action which is fired upon the creation of a new image, and feeds the generated image's file path to WP Smush under the hood. That's it.
 
+Obviously this plugin only pipes images through WP Smush that are generated after this plugin is activated. Old ones are left untouched. If you're looking to optimize images that were dynamically generated by Fly Dynamic Image Resizer in the past, check out [WP Smush PRO](https://premium.wpmudev.org/project/wp-smush-pro/), which is capable of Bulk Smushing / Directory Smushing.
+
 
 ## Our Company