The string specified as the ImageDirectory will be prefixed onto the DefaultImage, Tab.SelectedImage, and Tab.HoverImage properties of the Tab object.
Note that is a particular file-image-name starts with the ".", "/", "\\" character or contains the ":" character, then that file-name will be used as it is without the ImageDirectory prefix.
Target Platforms: Windows 10, Windows 8.1, Windows 8, Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2