I agree with diego. Using bitmaps from DOS is a fairly non-trivial task. Essentially you have to program the graphics hardware directly. You choose a graphics mode, exec a couple of BIOS interrupts to set up the display adapter, decode your image format (or read it from disk if its raw), extract the palette, write the image data into the correct places in system ram (the addresses the display memory is mapped into), and you have a graphic . Lots and lots of programming.
If you absolutely have to do this from DOS I would look at either a free image library or a shareware one like Fastgraph. But I would absolutely not jump through these hoops, as much of the knowlege you gain will be useless in any real world context. Best thing to do is program in Windows right from the start. To begin learning C++ you can just build simple console apps (essentially what DOS is under Windows), and then move on to using the .Net framework to build gui apps and display graphics.