There are many different types of videos that will require you to incorporate still photographs. Documentaries tend to be high on this list due to their historical content, or lack of footage covering a specific event or person. However, still photographs can be used in any type movie to add a certain effect or mood. Importing stills into your video is not hard to do. The tricky part is keeping the viewer interested in what they are watching. An easy way to avoid a bored audience is by using the pan-and-scan technique, also known as the Ken Burns Effect.
One way you can achieve this effect is by using keyframes. Keyframes allow you to move through your picture as if it were an actual scene. At it's core, you'll need to be able to edit the motion of your photo, place two keyframes for a slightly longer duration than you would a normal still photo (about three seconds) and change the position of the photo on the second keyframe. This will result in a moving image, but it may be nicer to have it start and end without movement, that requires a couple more keyframes on the ends.
A great example of this can be found in the beginning of Riding Giants when the narrator discusses the history of surfing. The still photographs are keyframed in such a way that they have just as much attention-grabbing action as the actual footage. One key here is being able to zoom into a photo, this way, moving the frame across the photo doesn't run off the page and leave you with a partially blank screen. Having a good enough photo to zoom in on is good since it allows you to effectively use it as a closeup. Using still photos in your video is unavoidable at times. Other times it is a conscious decision based on style. By learning pan-and-scan techniques, and mastering the art of keyframes, your videos will never suffer a dull moment due boring, static photographs.
For more information on adding movement to your still photographs check out Editing: Use of Stills in Video.