adding lightbox

Author: v-dirichards

articles/cosmos-db/mongodb/vcore/how-to-private-link.md

@@ -76,7 +76,7 @@ To create a private endpoint in an existing cluster, open the
 
 1. Select **Add private endpoint**.
 
-   :::image type="content" source="media/howto-private-access/networking.jpg" alt-text="Screenshot of selecting Add private endpoint on the Networking screen.":::
+   :::image type="content" source="media/howto-private-access/networking.jpg" alt-text="Screenshot of selecting Add private endpoint on the Networking screen." lightbox="media/howto-private-access/networking.jpg":::
 
 2. On the **Basics** tab of the **Create a private endpoint** screen, confirm the **Subscription**, **Resource group**, and
    **Region**. Enter a **Name** for the endpoint, such as *my-cluster-1*, and a **Network interface name**, such as *my-cluster-1-nic*.