I just realized I never provided a tutorial for this! I have tutorials on how to add a background and navigational bar/links, but not the banner. So see the instructions below for Blogger and Typepad.
- Login and from the Dashboard go to Layout.
- Click on Page Elements.
- Under the Nav Bar area you will see a gadget where you can click Edit.
- There you can upload an image for your banner (instead of title and description) by clicking the Browse button and choosing the image from your computer. You can also instead provide a website address if you have your image stored in Photobucket for example or other online image storage site.
- Then click Save.
- You're done.
- Login and from the Dashboard, go to your weblog.
- Then click on Design.
- Then click on Theme (for Theme Builder).
- Under the Banner section (first section), click on Image radio button and then click Browse to upload an image from your computer.
- Click Save.
- You're done!
Here is the link about what size your banners should be: