Board Thread:Support Requests - Designing Your Wikia/@comment-31916127-20160603230717/@comment-27073024-20160606024640

Since the URL for the image is pointed to the "latest" revision, you should still be able to use the Theme Designer to change / update the image.

If you ever needed to re-position the image, you would need to edit the CSS again.

PS: After using the Theme Designer, you likely need to purge your cache before seeing results.