depends on how you're making them. The limits for a thumbnail are 200x200 pixels, though I've had it get flaky when you render at that size (I use 180x180). If your program has the option to render thumbnails, try doing something at or below 200x200, and that should do it.

I wish I'd said that.. The Staircase Wit

anahl nathrak uth vas betude doth yel dyenvey..;)