That's why I turn to pixabay--a wonderful public domain site where I find most of the photos on my website. I love pixabay, and want to introduce it to you!
Pixabay graciously provides vibrant photos of everything you can imagine. The pictures can be used for nearly anything--school work, presentations, blogs. I fell in love the first time I saw it. The best part is: it's free! And if you're able, you can donate money to the photographers.