Improving custom list items performance, how?

Hello,

I'm evaluating Graphics Mill .net and am trying to build a custom list of thumbnails to be displayed in a filmstrip.

I'm using the sample code found in the documentation for custom list items and also the sample code for working areas. I haven't changed the code which loads the thumbnails and the three text items that the custom list items example is using (although my project will need to get some other information like a couple of IPTC fields, which will make this process even slower).
Unfortunately, when this code is applied to a folder of 10 to 20 files, the thumbnails are displayed really slowly and a folder of 15 jpegs of about 4-5 MB each, needs about 15 seconds to load completely. I even had a few "ContextSwitchDeadlock" errors when running this code on a folder of 75 files.
My tests have shown that the time / memory consuming code is the one that loads the custom items. Using working areas doesn't seem to slow down the app significantly.
How can I improve the custom list items code?

Many thanks.

Jacques