With Glimpses (was Briefly), still-motion videos are a neat and fun way to show hundreds and hundreds of your photos within a few minutes. (Still-motion videos consist of photos that are shown for the fraction of a second - though not to be confused with stop motion where photos necessarily correlate with each other and create the 'illusion' of animation).
Glimpses lets you create these videos with just a few clicks. Import your photos (from your hard drive, flickr or Instagram) and a soundtrack and Glimpses does the rest for you. You can then share your videos with friends and family right from within Briefly on Facebook, YouTube, Vimeo, and flickr. When you can't decide which photos to show, why not just show them all - with Glimpses.
Note: The downloadable demo is version 2.2.2; the version available for purchase on the Mac App Store is version 2.2.3.