Source : Free On-Line Dictionary of Computing

device independent bitmap
     
         (DIB) An {image} format in which the
        sequence and depth of {pixels} in the file is not specifically
        related to their layout in any particular device.  This allows
        any device dependent bitmap (DDB) image to be converted to or
        DIB format without loss of information, and this can then
        later be converted to other DDB formats for, e.g., printing or
        display.  Rather than requiring converters from each DDB
        format to all other formats, only converters to and from DIB
        are needed.
     
        DIB images are normally transferred in {metafiles}, {bmp}
        files, and the {clipboard}.
     
        Transferring colour bitmaps from one device to another was not
        possible in versions of {Microsoft Windows} earlier than 3.0.
        {Application programs} can build DIB images without any
        interaction with Windows.  If Windows lacks a drawing
        primitive, the application can simulate it directly into the
        DIB instead of using the existing {graphics device interface}
        (GDI) primitives.  Unfortunately, under Windows versions 3.0
        and 3.1, {GDI} cannot perform output operations directly to a
        DIB.
     
        Conversion between DIB and DDB is performed by the {device
        driver}.  Where the driver does not have this facility, the
        conversion is performed by GDI but only in monochrome.  DIBs
        are slower to use than device dependent bitmaps due to the
        conversions required.
     
        (1996-09-20)