In fact, there is a very interesting phenomenon taking place right now in the digital-camera market in regard to resolution. However, much of this demand is coming from the home market, where consumers are looking to digital cameras to replace their regular film cameras. However, in no case do we recommend a camera that provides less than VGA 640 x 480 resolution, regardless of the intended application. There are very few absolutes in regard to resolution, but rules of thumb abound. VGA images will probably be adequate for most slide or PowerPoint presentations, although slightly higher resolutions can be a plus if you need to really show detail or bring out natural flesh tones.
Web sites can get by with VGA as well.
VGA will do in almost all PowerPoint situations. If you want to show more detail, consider linking to a higher-resolution image for those who care. Remember that resolution alone doesn't translate directly to quality. Know your equipment. Even if you have a camera capable of high resolution, start with a VGA image and work up.