All of my stock folders contain the following advisory:

"For this folder, I give permission for the use of stock photos and resources for any use whatsoever, free of any obligations for renumeration and without conditions.

A link to my originals would be expected and appreciated if displayed anywhere online as the inspiration or subject of any artwork or photomanipulation, and I would love to see what use is made with any of these pics.

Thanks and enjoy!"

In other words:  I don't care what you do with it.  My preference would be that you show me what you do with it so I have the option to view and fave it, but that is not a condition, just a wish!  Make pics, prints, brushes, new stock, whatever... Enjoy!