Add screenies for publishing existing project

Author: jcansdale

docs/contributing/images/add-to-source-control.png

@@ -1,10 +1,14 @@
 # Publishing an existing project to GitHub
 
 1. Open a solution in Visual Studio.
-2. If solution is not already initialized as a Git repository, select **Add to Source Control** from the **File** menu. TODO: screenshot
-3. Open **Team Explorer**. TODO: screenshot
-4. In Team Explorer, click **Sync**. TODO: screenshot
-5. Click the **Publish to GitHub** button. TODO: screenshot
+2. If solution is not already initialized as a Git repository, select **Add to Source Control** from the **File** menu.
+![Add to Source Control](images/add-to-source-control.png)
+3. Open **Team Explorer**.
+![Open Team Explorer](images/open-team-explorer.png)
+4. In Team Explorer, click **Sync**.
+![Sync](images/team-explorer-sync.png)
+5. Click the **Publish to GitHub** button.
+![Publish to GitHub](images/publish-to-github.png)
 6. Enter a name and description for the repository on GitHub.
 7. Check the **Private Repository** box if you want to upload the repository as a private repository on GitHub. You must have a [Developer, Team or Business account](https://github.com/pricing) to create private repositories.
 8. Click the **Publish** button.