Most of the non-mathematics courses I've taken in college were done with lecture slides, and I have to say that there are a number of advantages and disadvantages to them that actually amount to more disadvantages if you were to do the same in math. The one obvious advantage is that the slides can be posted online, but the problem with this is that it encourages students to skip class. Even those who don't skip class won't take notes (and are sometimes even encouraged to not take notes by the professors), and this would not be good in a math class, because many people feel that copying down proofs from lecture is best way to get a better understanding of them. Also, when you have lecture notes, you can sometimes get nonsense like this. Anyways, back to your point. If your main concern is displaying graphics, you could possibly just use slides for graphics. If you can lecture in a room with a projector screen that doesn't obscure the blackboards, that would be ideal for this. Alternatively you can distribute handouts at the beginning with graphics that you will be referencing.