You can easily change the profile picture on the musescore.com website. Just follow the steps below:
- Log in with your MuseScore login details on the website;
- Go to your profile page;
- Click on your current profile picture;
- Click the upload icon and upload a new picture.
You can update your cover image the same way. If you don't currently have a profile picture or cover image, there will be an 'add image' button in their place. It is not currently possible to remove an image without replacing it with another one.