Board Thread:Support Requests - Getting Started/@comment-33969158-20170924024516/@comment-26923519-20170924050727

You mean the graphic that is in the page header? Well, you can do that step by step. You can also see Help:ThemeDesigner for full information. Hope this helped!
 * 1) Go to Special:ThemeDesigner in your wiki.
 * 2) Go to the "Customize" tab.
 * 3) In the "Page" part of the tab, there are 5 color squares. The first one indicates the header color. Click on the square.
 * 4) Change the color to a desired one.
 * 5) Click the "Save changes" button to publish the new color of the header.