What I do (in ImageReady) is to size the pic (I gave up on teaser thumbs when I read that some people disapprove of them, and won't view pics unless the entire thing is in the thumb - still don't understand why, but there ya go!)so that the largest dimension is 200 pixels, and then change the jpeg quality to 'medium' - usually comes out around 5 - 6k that way. Then again, my images are rarely above 800 pixels in any direction - I like them to fit on to my screen! Hope tht helps, too! :)