.

Save your new logo to  \14\TEMPLATE\IMAGES\AanuBranding\mylogo.png

Now go to : Site settings -> under Look & Feel  choose : Title, Description, and Icon

Logo URL and Description :  /_layouts/IMAGES/AanuBranding/mylogo.png

The Tip is relative path  “/_layouts/IMAGES” actually refers to “\14\TEMPLATE\IMAGES” folder