diff --git a/docs/twig-components/functions.md b/docs/twig-components/functions.md
index 2703ce2b..1dd079e2 100644
--- a/docs/twig-components/functions.md
+++ b/docs/twig-components/functions.md
@@ -294,8 +294,7 @@ For more information, see [Linking in templates][linkintpl-current].
 To insert an image in the HTML, which functions as an image popup use either
 the `popup` function or filter.
 
-You can optionally provide the width, height and cropping parameters, like you
-can do with the `thumbnail` filter.
+You can optionally provide the width, height and a class parameter, which will apply a custom class value to the image tag for styling. The default values of the parameters are 320 pixels wide, 240 pixels height, and class="bolt_img".
 
 ```twig
 {{ record.photo|popup(100, 100, "r") }}
@@ -440,4 +439,4 @@ Please refer to the [widgets][widgets-page] documentation.
 [previous_filter]: ./filters#previous
 [next_filter]: ./filters#next
 [markdown_filter]: ./filters#markdown
-[media_filter]: ./filters#media
\ No newline at end of file
+[media_filter]: ./filters#media