I think I am looking for pretty much the same thing, I would just like ZenPhoto to check if I have an image with the same name with _th after it before it creates a thumbnail for it. That way I can control the size and quality of the thumbnail, as well as what the focus of the picture is. My main problem with the thumbs currently is that in a lot of cases my images are completely cut off, where I want to show a downsized version of the whole picture...