Enter the internet. This medium continues to shake the core of the copyright law world. One of the more popular cases was Lenz versus Universal Music Corp. In 2007 a very proud mother posted a video of her daughter lip syncing to a Prince song, then posted it on youtube for all the world to enjoy. Universal Music Corp was not amused and forced Youtube to take the video down because they felt the mothers video violated their copyright of the song.
Thankfully Lenz (the mother) filed a suit against Universal for misrepresentation of the DMCA (Digital Millennium Copyright Act) and won. This case set the stage for what is considered fair use and good faith use of certain mediums.
That being said, the case was eight years ago, and the internet has only gotten bigger. The issue remains, what images can you use for free and what do you need to pay for.
There is no hard, concrete line of what is considered fair use and copyright infringement. It's more of a balance between the rights of the creator and public interest. There is much room for interpretation.
Currently, the fair use image copyright laws state that you are liable financially for posting copyrighted images, even if you:
Currently, it is within the creators legal right to sue a person or company for a million dollars or more (Agence France-Pesses paid 1.2 million) for copyright infringement. But does that make it right?
I don't think so. It boggles my mind that anyone can prove $10,000 or more in damages with an image that can be purchased on istock.com for $10. I don't see how that can add up. But whether I agree with it or not, the best advice I can give is: "buy it or don't use it."