Flickr holds an amazing, constantly growing collection of images from photographers around the world. Rather than "Any license" (which is the default), choose "All creative commons" when you search. Images with a creative commons license have "some rights reserved." These inform you what the creator will allow; be sure to check the terms for the image you want to use.
Offers a wide selection of quality food photography, sorted by 'type' (Breakfast, Dessert, etc.) Images on this site are licensed under a Creative Commons Attribution 3.0 Unported License, and may be shared or adapted, even commercially.
All images and videos on Pixabay are released free of copyrights under Creative Commons CC0. You may download, modify, distribute, and use them royalty free for anything you like, even in commercial applications.
From the website: A fascinating collection of science stock photos available for education and commercial use, high resolution and simple download. All photos on the website are licensed under CC BY 4.0 and can be shared and adapted.
Specialized Image Collections [Check usage rights in each case.]
A digital image library of Geological Survey of Canada maps. There have been thousands of maps published by GSC since the mid-1800's. More than 10,000 of these maps have been scanned and are available.