Cherokee... you can download any pic you have saved on your pc... it has to be no larger that 100x100 pixels, and I think 15000 bytes.
You can save any web pic to your pc or even use the url adresses, then go to the avitar section and the "browse" box. .. upload !
If you need to resize, use any imaging software... most have a "resize" option.
You can check the size by clicking on the pic's "properties"... then resize it if you need to using imaging software.
A great, FREE download is Irfanview.... (dot com)... check it out... it does a whole lot more than resize.
Hope that helps !