Hi everyone, thought this list might be useful for people wanting to make their own coverart and icons for their games. As with everything, always check the copyright status on the images as they can range from “personal use with credit only” right through to “public domain.” If in doubt, it can often be worth running a reverse search through (such as tin eye) to make sure that the image hasn’t been taken from a copyrighted source (particularly true for sites like deviantart unfortunately.) Also be aware that trademarked items within an image may cause a problem for commercial use even if the photo is free.
Some images will be marked with a CC number (for example CC0 is generally the equivalent to public domain). Others include perameters like SA (share alike), NC (non-commercial), ND (no derivatives), BY (attribution needed.) If your image is not public domain, you need to make sure you know exactly what the licence means and what it allows you to do with it so as not to run into any legal issues. There’s a few of them, so look up the type of licence for more details (you’ll find a lot of these on wikimedia in particular.)
Feel free to add to the list if you know of any other good sources.
In no particular order:
Sites that include free Images (Some may also include paid images depending on the site):
Wikimedia Commons. (A range of usage restrictions occur here.)
Gratisography (Be careful, some contain trademarked items within the photos.)
Vecteezy- Vector art. (Paid and free images.) Most need to be credited somewhere to use.
Deviantart (Mostly not available for use, but some are paid or free stock. Be careful with the usage restrictions and source particularly here.)
Dreamstime (Paid and free images.)
NASA commons on Flickr. (Worth a look even if you don’t need space related images. Very cool stuff.)