Thumbnail decoration of Image file-types

[Harsh J]

Hello devs!

Could I know how the Image type thumbnail plugin handles the
generation with effects ( as seen in this screenshot:
http://img17.imageshack.us/img17/144/whyt.png ) as opposed to the
thumbnails created by PDF/ComicBook/Etc plugins?

The image thumbnails always had these decorative shadow around them,
just like icons in the non-preview-enabled file view have. I've tried,
under ThumbCreator, the 'None' and the 'DrawFrame' flags but both
hardly bring out something even close to such an effect.

Looking into the kioslave/thumbnail/ directory for image plugins
didn't return results, or I maybe could not figure out what 'special'
post-processing they're invoking after generating the thumbnail. How
is this being achieved?

If is this a image-specific view feature, where may I find the handler code?
-- 
Harsh J
www.harshj.com