Hi Bev,

A Device Independent Bitmap (DIB) usually refers to a memory block that has been structured to conform with Windows API specifications for a DIB.
http://www.herdsoft.com/ti/davincie/imex3j8i.htm

I think that the bitmap option may be using the generic term for any raster image type. This could be a jpg, gif, png, etc. according to the format of the original image source.