Update howto-authorize-from-application.md

Author: vicancy

articles/azure-web-pubsub/howto-authorize-from-application.md

@@ -116,7 +116,7 @@ To learn more about how to assign and manage Azure role assignments, see these a
 
 4. On the **Headers** tab, add **Content-Type** key and `application/x-www-form-urlencoded` for the value.
 
-![Screenshot of the basic info using postman to get the token](./media/howto-authorize-from-application/get-azure-ad-token-using-postman.png)
+![Screenshot of the basic info using postman to get the token.](./media/howto-authorize-from-application/get-azure-ad-token-using-postman.png)
 
 5. Switch to the **Body**tab, and add the following keys and values.
     1. Select **x-www-form-urlencoded**.
@@ -125,11 +125,11 @@ To learn more about how to assign and manage Azure role assignments, see these a
     4. Add `client_secret` key, and paste the value of client secret you noted down earlier.
     5. Add `resource` key, and type `https://webpubsub.azure.com` for the value.
 
-![Screenshot of the body parameters when using postman to get the token](./media/howto-authorize-from-application/get-azure-ad-token-using-postman-body.png)
+![Screenshot of the body parameters when using postman to get the token.](./media/howto-authorize-from-application/get-azure-ad-token-using-postman-body.png)
 
 6. Select **Send** to send the request to get the token. You see the token in the `access_token` field. 
 
-![Screenshot of the response token when using postman to get the token](./media/howto-authorize-from-application/get-azure-ad-token-using-postman-response.png)
+![Screenshot of the response token when using postman to get the token.](./media/howto-authorize-from-application/get-azure-ad-token-using-postman-response.png)
 
 ## Sample codes using Azure AD auth