My entry images link to the full size image, as they should. The plugin configuration is all default values, but I noticed the last four plugin options are just empty div's.... The photo below shows the plugin config page of 2.4.0 (top) to another site running 2.0.3.

The plugin is not working as expected - on the new site. I upgraded the site running 2.0.3 to 2.4.0 and it still works, leading me to believe the old configuration values are unchanged in the upgrade thereby making that site operational.
Any thoughts?