A cool way to get fresh content-- pictures

So a few years back, I was working on my second book (soon to be converted to an ebook) and since it was a fairly technical subject, I was having a difficult time finding stock images, so I came up with a pretty cool idea and thought I'd share it with you guys and girls.

In my case, I was writing a book on safe motorcycling. I was also a frequent member on a motorcycle forum, which provided me with a ton of information on my topic. But then the time came to find engaging images to use. Sooo... I posted up a request on the forum and offered an acknowledgement and a free copy of the book to anyone who provided usable pictures.

The last step was then to get their email addresses and physical addresses. I sent them all a private message with some "right to use the image" verbiage. I didn't ask for all rights, just the right to use the image in any way I saw fit and gave them my email address to reply to with their name inserted and the specific verbiage. When they replied, I got their physical addresses, and just like that, I had hundreds of quality pictures taken by real enthusiasts, that were way more engaging than stock images.