An icon resource is an icon file (.ico) stored within a resource file. Each icon resource is identified by a unique index or resource ID. Icons are extracted from a resource file at run-time using the LoadResPicture function which takes the index and the format (1 or vbResIcon) as arguments.
Icon resources provide a convenient way to store multiple icons for an application while keeping the source files hidden from the user. You can use the Image Edit application (available from the Tools directory of the Visual Basic CD) to edit or create icons.