Some user report an incompatibility issue with version 3.0 of the NGG Smart Image Search plugin, which is not present in version 2.8 Beta.
The only difference between these two versions is mainly the inclusion of the color picker functionality on the settings side.
This should enable you to use the current version of the plugin.
After confirming the success of this small update, this version will be officially distributed to all users.
You can download this manual Update of the plugin here: Version 3.0.1
This update provides its own plugin directory with version number. You can just install it manually on your wordpress site.
You have first to deactivate your current release of NGG Smart Image Search. Then you can activate this update.
If you like, you can go back to your latest version by deactivating this update and reactivating your previous version.
This update also tries to optimize the theme-oriented searchbox styling.