Update Message_Components.md

Author: Lulalaby

docs/interactions/Message_Components.md

@@ -769,6 +769,10 @@ A text display component allows you to send text.
 | type    | integer | `10` for a text display component         |
 | content | string  | The content of the text display component |
 
+## Thumbnails
+
+A thumbnail component can be used as an accessory for a section component.
+
 ### Thumbnail Object
 
 ###### Thumbnail Structure