Hi - this is Cosmic Rocker - answering my own question so if anyone still has the original problem that I talked about in my post then here is a solution: let's just say you made a new playlist of The Best Rain Songs of the '70s. Now for the picture at the top left of the new playlist is pictures of the album covers of the first four songs in the playlist. But you want to replace those album covers for a pic you found on the internet like for instance:
I used to be able just to drag it over to that playlist and drop there where I want it. They took that away in Sonoma 14.2.1 So I figured out if you will drag that picture to a folder on you desktop - then back to you rain playlist, right click on it to EDIT and choose the square with the + sign in the middle, click on the + and you get two choices 1) Choose a file or 2) Choose from photo library. Click on option 1 and it brings up your Finder folder, go to RECENTS and there's the jpeg of this Rain Songs picture, choose it and hit OPEN and presto there it is at the top of you playlist instead of the 4 album covers. Sounds hard but it's not off if you want cool headers for your playlists. By the way this is me using an iMac with the Music App (formerly iTunes).