Add additional context to alt attribute

doc/user/project/releases/index.md

@@ -48,7 +48,7 @@ To view a list of releases:
 
 On the top right of the **Releases** page, you can use the sorting button to order releases by their "Released date" or "Created date" and sort releases in ascending or descending order.
 
-![Sort Releases](img/releases_sort_v13_6.png)
+![Sort Releases dropdown button](img/releases_sort_v13_6.png)
 
 ## Create a release