Remember that when using images in your work you must identify where you got the image from and, if needed, get permission from the owner of the image to use it in your work. Many of these sources place restrictions on how the images can be used. Follow the usage guidelines provided, and avoid the risk of plagiarism by citing the source of any images you find on the web.
Explore these sites to find copyright-free images for your work. Always check the licence on each image to make sure it is free to use and doesn't require attribution.