Here you can find various open source website, from which you can access open source images to use.
https://unsplash.com/
https://www.pexels.com/
https://picjumbo.com/
https://globalowls.com/free-stock-photos-nonprofit/
https://pixabay.com/de/
opensource logosĀ https://thenounproject.com/search/?q=registration