Can I legally use static vector images downloaded from freepik or pixabay to create my own animations and then sell them? Their license terms are a bit confusing for me. They say that I can use those assets in personal and commercial projects as long as I include attribution. But at the same time they disallow selling any "derived work". Do my animations count as derived work?
What if I buy a pro account on these services, which frees me from including any attribution. Can I then create and sell such animations?