Of course, you do not want to copy other artists’ work. Besides violating copyrights, it’s just unethical.
But why not learn from copying? Many artists paint old masters paintings just to learn how to do it. And you do learn a lot. As long as you aren’t selling it, or passing it off as a real old master, you’re good.
But another way of learning from copying is to paint photographs. You take the photo, so it’s your copyright, and no problem. There are a number of ways to do this. You can paint or draw by just looking at the photo and putting it into paint and paper or canvas. You’ll learn a lot from doing that. But most new artists who try that just give up and say they don’t like their own painting.
In order to teach one of my grandsons some art lessons I got him a “light table.” The one I got cost about $10 and it is a very thin piece of plastic which plugs into a computer port and lights up. Then you put your photo or whatever you want to copy on that and a blank piece of paper on top and the light shines through and you can draw outlines and shading of your subject.
The grandson has been very enthusiastic with it – he’s done about 30 drawings of things he would never draw just off the top of his head. And the result is that now he knows how to draw them.
I just recently tried it out myself, and it’s so much fun, I can’t get enough. I’ve been drawing faces and buildings and although I paint these subjects without the “light table” I have learned a lot about the details that go into making a good drawing by using it.
Think it’s cheating? Well, old masters had their little shortcuts, too. Look up camera obscura (“Camera obscura, also referred to as pinhole image, is the natural optical phenomenon that occurs when an image of a scene at the other side of a screen is projected through a small hole in that screen as a reversed and inverted image on a surface opposite to the opening.” –Wikipedia.) It was used to make drawings for paintings back before cameras. Tools of the trade.