Expanded Use of Silhouettes
Take a look at this slide, which introduces information about an upcoming event. The two design elements are vector drawings purchased from a stock image site.
It's simple and clean and a nice departure from photographs. Photographs are the "go to" image type for most slides, but there are some really nice vector graphics and illustrations that tell a very pretty story. The reverse silhouette (white) of the sailboats is a nice touch.
Stock image sites have amassed a tremendous collection of illustrations and vector graphics over the past few years. Sometimes they tell a better story than photographic images. Additionally, stock image sites are beginning to restrict the use of the photos in some cases. For example, if you searched for a photographic image for a regatta and the search produced images from real regattas, it is likely that the images would be for "editorial use only." That means that you wouldn't be able to use them in your presentations. Silhouettes are a great alternative, and they will never be restricted for editorial use only.
Keep this idea in mind for a nice, alternative to using photographs in your presentations.