The first image was inserted without a link. SLB requires links to media so that it knows what to display in the lightbox. Wrapping the inserted image in a link to a larger version of the image should do the trick.
The second image is properly linked and I can confirm that it is not working. This is because something is keeping SLB from loading fully. The most likely causes of this is that the theme is causing a conflict or there is a conflict with another plugin.
The simplest way to test if the theme is causing an issue:
- Temporarily switch to one of WordPress’ default themes (e.g. TwentyTwelve)
- Clear the browser’s cache and reload the page
If SLB works properly then the issue is with the theme. The theme you’re currently using, Good News, appears to include its own version of jQuery, which means it may also be deregistering WP’s own official version of jQuery. If so, then all plugins that require WP’s version of jQuery (such as SLB) will not be loaded properly.
The simplest way to test if there is a conflict with another plugin:
- Deactivate all plugins except for SLB
- Test to make sure that SLB is now working properly
- Activate a plugin
- Reload the page to test if SLB is still working properly
- Continue activating a single plugin and testing if SLB continues to work properly
- When SLB stops working, you have identified the plugin that is causing a conflict
My recommendation would be to check for an issue with the theme (using above instructions) first. If SLB still is not working, then proceed to test for conflicts with your other plugins.
Let me know what you find.