I'm building e-learning site by moodle. I add image as banner at Settings-> Site Administration -> Appearance -> Additional HTML. It is shown after login but can't show before login. Please, can anyone provide a suggestion to this?
Go to Settings > Site Admin > Front page settings and tick "Include a topic section"
There are a number of other useful settings on that page, such as what users see before and after they log in.
You then need to add a Resource ("Label") in the Topic section on top.
Where do you want the banner to appear? Is it a site logo? Should it be in the header? Footer? Sidebar?
If it's a logo in the top left corner you're after, use a theme that supports logos such as Afterburner.