Today I learned a great lesson about the use of copyrighted images online. Never use copyright photos taken by someone else without their explicit permission in writing, even if you give them credit and a backlink to their website.
You never know what model release rights photographers may have had with their clients, or who they may have shot the images for, and your using of their images may violate their contracts and not only cause you to get in trouble, but them as well.
Fortunately I didn't have to learn this the hard way. I recently wrote an article about "Why Photographers Crop Off the Tips of Heads in Headshots," and I used a number of images from other big name photographers in New York, such as Peter Hurley, Chris Macke, and Taylor Hooper.
I decided to email Peter Hurley with a link to the article to ask his permission to use the photos and to see his thoughts. He replied asking me to please remove the photos as soon as possible because of model release issues and having to deal with backlash from clients, managers and agents, and I did so right away.
I learned that even posting an image up on a site for a few minutes is not worth the anxiety it could cause the photographers who took the photo. And of course if the clients did complain, things could get much worse.
So the lesson for today: ask always before posting an image you didn't take. The backlash and problems that can occur are just too great to take the risk. And it's wrong anyway to do it without someone's permission.