An ad format is a web page branding with a single image panel, or multi image panels - left, right and, optionally, top. Multipanel branding may contain different target URLs for each panel.
Branding: width and height depend on a web page layout. Make sure that the banner content (top, left and right sides) is aligned as close to the website as possible, so it is visible on most screen resolutions. The website background color should be considered on the borders of the banner-to-website background transition.
Branding panels are images.