They are different lossless image formats. What is called "raw" is quite a few different formats from different manufacturers, and they contain lossless image data from the camera sensor without significant postprocessing. They usually need some postprocessing to look "good". A "bitmap" is just pixel data, not a file format, but .bmp is a file format, which does support some compression, and usually won't contain raw camera sensor data but something ready to be displayed on a screen.