A bitmap resource is a bitmap image file (.bmp) stored within a resource file. Each bitmap resource is identified by a unique index or resource ID. Bitmaps are extracted from a resource file at run-time using the LoadResPicture function, which takes the index and the format (0 or vbResBitmap) as arguments.
Bitmap resources provide a convenient way to store multiple images for an application while keeping the source files hidden from the user. You can use the Windows Paint application to edit or create bitmap files.