If you forgot to un-ZIP, fix it — but don’t tell anyone. There are some quality posts from others such as this recent one, Things I Wish I Knew When I Started Using Thesis that can supply ideas and help at these most basic levels — an example being recommended FTP clients. Banner Image types, quality, and recommended formats. You can go with a GIF, a JPG, or a PNG as common image types.
If that was nonsense, click here to see what we mean. We’ll not go into detail here, aside from noting again that your width should be the discovered pixel size from the step above or other estimates, and that you should export and save your image as a JPG or PNG in the majority of cases for a crisp custom header banner.
If, as in our example, you see “959×364” you will have your target banner image width: 959 pixels. The height of your banner image is all yours to decide. Also, the larger the rectangle (image), the larger the file size, which can slow your load times, eat your bandwidth, and generally annoy Mother Earth.
If it does not, your absolute path is not what you thought it was.
The advantage — for novice Thesis users — of an absolute link/URI is therefore the ability to confirm the image is where you feel it should be before you begin editing any custom files.