When you access WXForum.net (or any site) with HTTPS, the images/scripts that are referenced using HTTP may not be shown, and it's a browser thing. Various browsers handle it differently. Some will display the images and most will not load any http scripts from offsite. It's all part of the rules regarding mixed secure/insecure content displays.
If you have https available on your site, just change your link in your profile to use https and the image will likely show again.