Add a Custom Header Image to a Blog (Professional Web Site Template)
Step-by-step instructions for replacing a default banner by adding a custom header image.
1)
Create or select an image that is 905 x 170 pixels. If it is bigger
then just the first 905x170 pixels will show on the Web page.
2) On your dashboard, select Upload File under the Create tab. Click Browse to select your file and then click Upload.
3) When the File Options screen appears deselect “Create a new entry using this uploaded file”, add the tag "@banner" in the tags field, and then click Finish.
4) Rebuild your blog.