Finding compelling photos to accompany your blog posts and e-newsletters can be a real struggle. Fortunately, there's a new site that offers free, beautiful images that are public domain - which means they don't even require attribution to use.
Unsplash is an incredibly minimalist, almost retro-designed Tumblr site that posts ten new photos every ten days - and you can even subscribe to receive new images via email. To quickly scroll through all the photos they've posted and choose ones that work for you, check out their archive.
Unfortunately, the site lacks any kind of search function, so if you're looking for something very specific, this isn't a good site to use. (Try Stock Xchange instead, and use the Advanced Search and choose "No" on the "Restricted OK" dropdown.) However, if you just want to quickly build a library of beautiful images you can use without restriction, Unsplash a fantastic site.
Check out some of the images they offer below.
Edited 2:29 p.m. 2/3/14 for accuracy regarding search/tagging.