Re: Another Reference Image Library
I stumbled on this site myself and was going to mention it. It is amazing!
"All photos on Pexels are licensed under the Creative Commons Zero (CC0) license. This means the pictures are completely free to be used for any legal purpose.
The pictures are free for personal and even for commercial use.
You can modify, copy and distribute the photos.
All without asking for permission or setting a link to the source. So, attribution is not required.
The only restriction is that identifiable people may not appear in a bad light or in a way that they may find offensive, unless they give their consent. You should also make sure the depicted content (people, logos, private property, etc.) is suitable for your application and doesn't infringe any rights."