This was probably asked a million times but today is my first day setting up my blog here at wordpress.

I have a graphic, that's less than the 740 x 192 pixels recommended on the site. When I upload the image, it cuts it in half. How come? I google searched and was told to do this this and this but I don't even know how to navigate through this site yet. If someone could give me step by step directions, that would be great!!

Right now I'm just going with a basic white screen since my logo is black and white so no theme is necessary.

what version of Atahualpa and WP?
What is the url so I can see the issue?

Are you talking about a header image or a logo?
What have you defined your header image height to be? (ATO->Header Image->Header Image: Height)
How wide have you defined your page to be? (ATO->Style & configure LAYOUT->Layout WIDTH and type (FLUID or FIXED))