Derivative Images Plugins

Dear Omeka Forum friends

I wanna ask. I still dont`t know the function of Derivative Images plugin. Could you explain the function of the Derivative Images.

I try to install Derivative Images, but its still not success yet. Theres notification that The ImageMagick directory path has not been set. No derivative images will be created. If you would like Omeka to create derivative images, please set the path in Settings.

How to set The ImageMagick directory path ?

Thank you.

The path to ImageMagick can be set in

The plugin allows to recreate derivative images (thumbnails) when their sizes are changed in