Well, on Internet, you can get lots of things just for free. For example, you may hit upon PDF files containing an entire issue of a given volume of a scientific journal. Or you may get videos, photographs, and/or artworks for free.
In the case of getting pictures, the headache is not all about whether or not it is free of cost. The headache is about user rights.
Most of the images that come along with unrestricted permissions to reuse can be got from the sites like Shutterstock, Alamy, etc. The websites like Flickr give their images under the Creative Commons License. All the other images or pictures available over the Web are copyright protected.
