If the above doesn't work,locate your keyboard ... press your ctrl - alt - del keys at the same time, two times.
Here we go again, I think that most here forgot that the max size of your avatar has to be no bigger than 125x125 pixels!!! And there seems to be no images smaller or the same size at google or yahoo!!
Just get which ever picture you like and use photoshop or some other picture editor to resize the image and reduce the quality (if needed). It's really hard to find a picture that you want that is exactly perfect for an avatar, unless you take someone elses avatar which was probably resized with photoshop.