Virtualmin has the ability to display a logo in the top-left corner of the framed theme that is customized by the master administrator, perhaps for his hosting company or ISP. This field allows you to override that logo for customers of this reseller, who may have his own company and logo that should appear instead. Or you can select No logo to not display anything for the reseller's customers.

Typically, you should enter a full URL like `http://www.resellerswebsite.com/logo.gif`, but relative URLs for images that are in other Virtualmin modules are also allowed.

Although the exact allowed size of the image depends on the browser being used to access Virtualmin, the image should be at most 220 pixels wide. The height is not limited, but 120 pixels seems like a reasonable size.