Why do many people think that a sketch is not a picture? These pictures I found on Pinterest, and I was inspired. Yes, this is plagiarism, but it's part art too. Because not everyone can correctly redraw, and draw shadows and gradients. And I ask you not to condemn beginner artists for plagiarism because, in order to learn how to draw, you need to take an example from experienced artists. It’s fine as long as you’re mentioning the author and not saying that the idea is yours.