For images not loading or displaying, there are several things to check:
- Check the permission settings on the upload folder(s) by ensuring that you can successfully upload image files thru the Media Uploader.
- Double-check that all the image-upload settings make sense, and that the images being uploaded meet the specified requirements.
Note: when changing permissions on files and folders, it is important to use the least-restrictive settings possible. If you have to use more permissive settings, it is important to secure the directory against malicious activity. For more information check out http://digwp.com/2012/09/secure-media-uploads/
For template tags, place them in your sidebar.php or page.php (or anywhere in your theme template). For shortcodes, place them in any post or page.