Stock photos are photos that are available for immediate use. They are cost effective alternative to hiring a photographer to go out and shoot the photos.
If we had to go out and hire a photographer for every blog post, that will be a handsome load of work on our shoulders. So an alternative is to visit a website and download already existing and related pictures for out articles.
There are almost unlimited number of stock photo websites out there offering both free and paid options. Generally, the difference is in terms of size and resolution. But before I give you a short list of some of the stock photo sites I use, we are going to see some important points.