We've all downloaded software that has Agree and Disagree buttons. To complete your download, you have to click on the Agree button. If you click Disagree, you will lose the ability to install the software. Lengthy legal terms can tempt you to click Agree before you read them.
Like software downloads, many Internet stock photo galleries use similar buttons. They advertise their images as Royalty Free. There, too, the temptation is to click and continue. However, although the photos are Royalty Free they are not free. Look at upper-end galleries such as Getty Images, Corbis, or National Geographic.
If you have to pay, what is Royalty Free?
Royalty Free galleries sell licenses to use their images. However, buying a license is not the same as purchasing the image.
A royalty is a per use payment to the holder of a patent, copyright, or other intellectual property. For instance, each time a TV station runs a program, it likely pays the producer for that presentation.
The bottom line: Royalty Free is not Really Free.