Another useful little One Pager that provides images to use for your app sourced from 500px or Flickr provided under Creative Commons Attribution.
This website has unfortunately been redesigned or gone offline, so I have removed the direct link to it. The screenshot below hopefully preserved enough of the design but if you are really keen to inspect further, try this Archive.org link. FYI: the site was first featured on 27 March 2013.
Features Big Images Blue Color Full-width Layout Icons Useful
Category App, Digital Product, Landing Page,
Published 27 Mar 2013