OrangeCD doesn't seem to store my thumbnails.

Whenever I open the catalogue and look at the entire collection or an artist folder, the thumbnails take a while to load, and the status bar says "Generating Thumbnails" and the percentage indicator.

My "Imaging" settings are: "Store covers in external files if size exceeds 0 KB." I also have the "Store thumbnails in the database" box checked.

How can I make OrangeCD truly store the thumbnails, instead of regenerating them every time?

Thanks.