All images are licensed under the Creative Commons Attribution-ShareAlike 4.0 International license. That's correct, they are all under the same license.
That means you are free to use the images for your own creative projects including commercial ventures. The main thing we ask is that you:
We ask that you do not use any images available here, either for free use or as part of the premium membership, for the promotion of hate speech, pornographic materials or any other use that is beyond the reach of human dignity. If you have to ask what that means, don't use them for that. We will find out.
Secondly, release documentation will need to be secured for any individuals or trademarks featured in the images found on Stock by Arias & Thompson. We will not be providing any releases with any photos making it your responsibility to secure that release if required for use commercially.