[Plugin: GRAND FlAGallery – Best Photo Gallery] Cropped thumbnails

Hi,
I installed the plugin and it works OK. But thumbnails are just cropped images. So you can see only very small fragment and sometimes no idea what it is…
How can I create thumbnails like – thumbnail of whole picture instead small fragment?

Thank you in advance,
You can see my example here: Fleurs

http://wordpress.org/extend/plugins/flash-album-gallery/