Newbie Needs Help-Changing Picture
 

OK, I thought i would post my quandary here. My friend is hosting my site and I have the Atahualpa 3 WP theme. I am so new to this I do not know where to look to change the default picture to one of my own. I read some prevous posts and still do not understand. Just not sure while files to look in on Word Press or under the FTP on the server. Any help would be greatly appreciated. Thanks
Dave

I found a thread and did it. Now to figure out how to stretch the pic