A lot of members have dial up connections to the internet and the large avatars take quite a long time to download. They also throw off the position of the text in the thread. If you haven't already done so, please resize your avatar picture to a maximum of 100 pixels in width, 120 pixels in height, and the file size should be no larger than 8kb (when you go to upload your avatar it tells you this, so don't think I've pulled these numbers out of the air!).
Please remember the size of your photos as well. Most of the hosting sites have applications to resize your photos. They don't have to be as small as the avatars, just a reasonable size where one photo doesn't take up the whole screen. This effort will be much appreciated by the folks with slow internet connections.