Somehow I always have the feeling that many artists see repainting of other works a little too negative. I see it quite differently: Especially if you are still young and have not yet found your own style, you should calmly copy or repaint other images. I'll explain here why and when it can be useful in my opinion. So people ... do not worry, it's fine! If you don't need to, consider yourself lucky. The rest should definitely do it.
The own style
I used to look for my own style in my paintings; I tried many things to force that style. At some point, however, I decided for myself that my own style cannot be forced. You may not be satisfied with your current works, but that should be motivation to keep practicing. I think many aspiring artists also want to find their style, and a good way to speed up this process is actually by re-painting images. More specifically, from images of your favorite artists.
Learning by copying
You should think of copying from better artwork as a kind of learning exercise. It's just like learning languages: if you only learn a language with a book, you will eventually realize that your accent is disastrous. But if you practice with a native speaker, you will have a much better pronunciation.
It is similar with art. Studying others' paintings should be an essential act for every artist. This includes duplicating images.
In order to understand how a painting was made, it is very helpful to try it yourself. This also increases the chance that your own works will eventually look more like the ones of the model. This is the kind of "practice" painting you should do every once in a while to develop your skills. Another exercise I can recommend is tracing from photos.
Is it okay to trace?
And now we come to taboo topic number 1: tracing. (Oh dear, now I've written the bad word.) Is it allowed? Well, that's something everyone has to decide for themselves.
I think it should be "allowed" for some things. Why not?
For example, for the hated painting of hands. Hands are particularly tricky because they quickly look pretty ugly. To paint hands properly, there are several methods, but in the end, it doesn't matter later how they were painted. The main thing is that in the end the fingers look the way they should. I think that if you can't do it on your own, you should use templates and paint or trace the fingers and hands.
Copy yes, but also create something new
Many pictures are simply not painted to the end, because they are too difficult and it is demotivating if you do not get further. Who would blame you if you took some help in the form of templates? But please don't start your browser and copy the picture of a digital artist one by one and then sell it as your own! If you already copy or paint something, then please do it in such a way that it becomes something of your own. This is about practicing and learning not about standing out with other artists' work.
We don't want to plagiarize, we just want some help. If you can't paint a body, then go ahead and find templates and paint them, but add different clothes, change the hairstyle and face, or maybe hold an arm differently. Create a work from the template that you can proudly contemplate at the end.
Paint, learn and become a better artist but be fair in the process.