Copyright protects not only pieces of music, but also other creative works such as pictures, graphics, text and video.
In principle, any work created by someone else is protected by copyright. It is therefore important to be aware that using such works without the author's permission is an infringement of copyright.
If you want to use an existing cover for your album, you should always ask the author for permission. It is important to note that even if the author has given verbal permission, you should still get written confirmation so that, in case of doubt, you can prove that you have permission to use the work.

Using someone else's work without their permission can have serious legal consequences.
Therefore, as an artist, you should always make sure that you only use works for which you own the rights or for which you have obtained a licence.

Here you will find the requirements for artworks: