Avatar
If you want to change the Avatar (the little image next to your comments), you can do so easily by setting one up centrally at GRAvatar. This is a default service used by Wordpress, which I cannot change. It is supposed to work with many/most blogs.
Comments
To avoid spamming, the first time you post a comment it must be approved. I only deny spam-comments or ones that contain heavy self advertising and/or may not be related to the topic and/or may have legally questionable content.
Being faced with 60+ spam posts on a single day, I added captcha support, requiring posters to enter a code before posting. I know that is a little inconvenient, but appreciate your understanding!