This is covered in the troubleshooting post.
if your image is not showing, is it accessible on a URL that is not blocked by your robots.txt file? Does it conform to our size constraints? Are you using an absolute and full URL (including the http protocol piece), not a relative one?
None of your image tags include the protocol (https). Additionally, by including three image tags, the crawler will only be able to pick one, and this may not be what you expect.
