Here is a free program for all to use as long as you are a private user of it[commercial (Biz) users must pay for it]. Irfanview makes an image resizer program that is real handy, not for just avatars but all your image needs. Go to www.irfanview.com
Once you have down loaded the program, open it up and select your image to be resized. On the image pull down tab, click resize, and you have infinate sizing options. Also you can save a bit file as a jpg file. This makes a big difference on what a person can actually see in image size like a 6 x4 instead of 3" x2"as many sites have file constraints too.
Also remember you need to be registered to use an avatar here at DHC.