As a writer that sells my Intellectual Property for actual money I have come to understand and respect other folks IP as well. Not only their writing of words but their Art, Photos, Music and more.
I use a lot of images in my Blogging for instance. I also create my own covers for my Kindle short stories. I use copyright free images.
The easiest way to find the images you need that you can reuse is though the advanced search options of Google Image Search.
--Give it a try.