I guess there is way more that can be added to the list. If you know sites that aren’t here, let us know in the comment and we will add it to the list.
Before we start let me explain a bit about how to use the websites listed. The fact that the photos are FREE doesn’t mean you can do whatever you want with them. At least not with all of them. Some require registration, some don’t. Some require attribution, some don’t. Some have are goldmines of free photos and some have a few which are great.
There are different terms and conditions that apply so it’s best to check them at the website you want to use a photo from before you use it in your project. The most general rules are these:
- CC0 – Public domain – you can do whatever you want
- Creative Commons BY – attribution required – you still need to pay attention to other conditions.
To get a better understanding check out Wikipedia.