How to automatic coverdownload without changing any other tag?

Tags: #<Tag:0x00007f7d00e4d098>

I have a huge collection of already tagged music and would like to download covers and embed them into the files.
I worked in the past with easytag under linux and use more and more musicbrainz picard under Debian linux.

I have seen in the options that I can exculde fields to be overwritten. The documentation is quite abstarct in this point and I do not understand it.
What do I need to do, that musicbrains Picard only downloads the cover and does not change any of the fields? Maybe somebody has already a solution?

Searching google doesn’t help me, all the findings were to generell.

Some help would be nice. Thank you :slight_smile: