But it tends to offend the audience, and I recommend you avoid doing it. Don't advance your slides too quickly or go from one overhead to the next in a hurry. Keep each image on the screen for at least 12 seconds. With more detailed images, leave the image up a little longer. If you change images too rapidly, your audience won't have time to absorb the information.
Enthusiasm is contagious.
Make sure audience members in the back of the room will be no further from the screen than eight times the width of the projected image. Mix text, charts, and photographic images to keep your presentation interesting. Too much of the same kind of image is tedious on the eye and boring. And make sure to fill the image frame, leaving only a narrow border around the edges. Some people have the artistic talent to make terrific visuals by hand, and it's easier to use color that way as well.