it is suppose to be falling back to the "default" avatar in this case, but there seems to be a bug in n2a. I'll get an update out in a few days (as i am also updating how images are generated, to improve speed and what can be done with them. like the clubs feature if you used it, would have noticed it has an image overlay to it, with color's and text, i am planning on bringing a similar feature to the avatars/monsters/forums and downloads, but it needed a fair bit of work to the image generator.)