add image showing how to open Prompt Playground

Author: willydouhard

concepts/prompt-playground.mdx

@@ -8,7 +8,11 @@ Being able to visualize the intermediary steps is great, but what if you want to
 
 No! You can do all of that from Chainlit UI.
 
-Below each message you will find an `edit button` if that message was generated by a prompt. Clicking on it opens a prompt playground, allowing you to modify and iterate on the prompt as needed.
+Below each message you will find an `edit button` if that message was generated by a prompt.
+
+![Playground](/images/open-playground.png)
+
+Clicking on it opens a prompt playground, allowing you to modify and iterate on the prompt as needed.
 ![Playground](/images/playground.png)
 
 To iterate, remove the previous completion (the text highlighted in green), and edit the prompt as needed. Then, click on the `Submit` button to generate a new completion.