Header sizes & background

Hi, I have downloaded the Fashion theme and have uploaded my logo many times as well as another. My problems are as follows:
1. My logo never fits in the left hand corner as it should and another time it covered the entire header page where the welcome photos goes. I have tried moving it or looking for a place that allows me to minimize the icon on the dashboard and such but have not found anything. If there is a particular size needed for this theme or some place that I can be allowed to adjust it I would like to know.

2.The header background does not change even after I have selected an image. It appears on the dashboard but not on the website.

Any help would be appreciated. Thanks