Sometime you find sprites on the internet which although on royalty free sites, claimed to be authors own work, may actually be ripped from other games. If I took these sprites in good faith and made a game with them would I be breaching copyright if A/ Used them in an original game and shared that game with no one else at all. B/ Used them in an original game and shared it freely with public via internet C/ Used them in an original game and sold it to the public via the internet. Bearing in mind if the intent to breach copyright was not there, i,e. it occured unknowingly. What should be the correct course of action from someone who would claim the copyright?
The safest thing to do is just create your own. It's for reason like this that I always shoot my own photos, and create my own graphics.
You could seek the original authors permission to use them? Just be clear on what you want to use them for and get written consent.