Public ≠ Public Domain
This question was recently posed to me:
If a photo is posted online, I can safely assume it’s considered part of the “public domain,” right?
Nope.
Every photograph, published or unpublished, taken by a U.S. citizen, or on U.S. soil since March 1, 1989, automatically belongs to the person who pressed the shutter button (or their employer/client, if the photography was in the course of their profession). (Photos taken between January 1, 1978 and February 28, 1989 enjoy similar protection, but it requires additional documentation, as they are not covered by the Berne Convention.)
As per the Copyright Act of 1976, photos taken by a U.S. citizen, taken within the territorial confines of, or published in the United States enjoy copyright protection without the need for registration, watermarks, or accompanying copyright notices. The copyright lasts, at minimum, 75 years from the date of first publication (and no, posting to flickr isn’t considered publication by the U.S. courts).
Furthermore, like many photographers, I take the extra step of registering every single photo I take, be they family snapshots, landscapes, abstracts, or artistic nudes, etc., with the U.S. Copyright Office, so that I’m afforded the complete protection under Title 17 U.S.C.
If a photo is registered with the copyright office, regardless of how it’s used, or whether or not any profit was derived from its use, the registered owner can sue the infringer for $150,000 per image, plus any actual monetary damages/profits incurred.
Even if the photo isn’t registered, but falls under the aegis of the automatic copyright provisions of Title 17 U.S.C. and/or the Berne Convention Implementation Act of 1988, the owner can still sue for actual damages and “disgorged” profits — this fact alone, aside from being generally polite and good karma, is why you should ask, first, before using an image that you don’t have a license for.
(And for those who wish to claim Fair Use protection, as defined by 17 U.S.C. § 107, posting a high-resolution copy, or providing an attribution link do not, in and of themselves, justify the reproduction of a copyrighted work.)
Most photographers, myself included, will be extremely flattered and more than happy to provide you with a licensed, usable image, so long as it won’t be used for commercial purposes.
More than anything, it’s about respect. If you like someone’s work (and even if they make it look effortless, make no mistake, it’s taken hard work to get there), respect them enough to ask first.
(Source: copyright.gov)