Appearance - Header
The Header screen allows you to add a banner image to your website.
Click on the Browse button to upload a JPG, GIF or PNG file. Note that the size of the original image must be greater than or equal to the given dimensions or your image will be stretched/skewed.
You’ll be brought to a screen where you can crop the image to your liking. When you’re finished, hit the Crop Header button and you will see your custom header as it appears on the website: