Pointless topic is pointless. For many reasons.
It will be a shitty-ass avatar and you won't be happy with it. And what if you want a signature? Both are the same fucking shit, only that signatures are bigger most of the time.
And let me ask you a question: Then why have Photoshop/GIMP/etc.? Obviously you use it to make a graphic with better quality. Googling something and putting your name on it sucks so fucking much.