The ability to display a small number of random photos from a larger collection had been requested by a few users.
It required a bit more development than just making a random selection as it needed to implement a caching strategy in order to perform well and remain within Flickr’s terms of service. It does not make sense to fetch the information about 200 photos and then only display a random 20 on the page every time the page is refreshed. What the plugin does is cache information about the 200 photos. Then each time the page is refreshed it randomly chooses 20 from the cache and displays those.
I see this feature being most commonly used in a text widget in the sidebar on in a footer which appears on every page. This adds variety to the site as different photos will be displayed on every page visit.
Here is an example of 6 photos of my dog Roma taken problem a selection of 60.
slickr-flickr type="gallery" tag="roma" items="60" random="6"
Refresh this page to see different 6 photos of Roma.
