When you take the time to create a professional report it can be useful to include your company logo. If you insert it in the header of an Excel worksheet it will print on each page of the report.
(http://reallyusefultraininganddevelopment.ie/wp-content/uploads/2011/11/image_thumb15.png)
Go to the Insert Ribbon
Insert, Header & Footer
Click the Picture button
Choose an image to insert.
If the image is larger than the header, it will appear around and below the worksheet.This is because the image is not automatically resized to fit when you place an image in a header or a footer.
To resize the image
Click the View tab.
Click in the header or footer section where the image is located.
Click in the &[Picture] text of the image.
On the Design tab under Header & Footer Tools
Click Format Picture in the Header & Footer group.
On the Size tab, adjust the size of the image to fit inside the header or footer section.
Click OK.
Source: Really Useful Website