The simplest digital presentation is probably made using a laptop or desk-top computer in conjunction with images written onto a CD or DVD. All the organization of the images can be done in advance, so the quality of a presentation is entirely predictable provided everything works correctly.
Presentations can also be made by connecting the VGA or DVI-D output from the graphics card of a personal computer to the appropriate input of a modern television set. The computer's graphics card should ideally be capable of driving two monitors simultaneously, perhaps using Invidia Nview software, giving the operator freedom to control the computer in the normal way while the audience views the presentation on a larger screen.
For larger audiences, it is preferable to use a digital projector to throw an large image onto a traditional slide projection screen. Such projectors are now obtainable at reasonable prices, although the lamps are expensive and easily damaged. The colour balance of the projected image must be properly calibrated to obtain satisfactory and consistent results.