Unsplash offers Huge selection of royalty-free images that get updated often. There are albums of different images that can be downloaded and used in your projects (with attribution). There are artists and photographers that contribute often and provide lots of different options. These are generally very inclusive and allow you to find the best option for your project.
It is also very easy to use and there are lots of photo options out there.

Note: this app is for review purposes.
Credits to www.unsplash. com