One on my main gripes with the Gallery app is that it finds all pictures on your Droid. The adding a .nomedia file to the folder does not work as the files in the folder are no longer available to the Music app.
I have My Music organized into Artists, then under artists there is a folder for each Album/CD). While browsing through the MY Music folder on the SD card (I use the free app ES File Explorer, there are several others that also work well), I noticed that each Album/CD folder had a file called "folder.jpg". To my surprise, this was the Album/CD cover. I then removed all other copies of the album/cd cover and low-and-behold when I opened the gallery, the album cover did not appear. I then tried the music app and the album cover still appears. I did this to a couple of albums.
I had one music folder that did not have a "folder.jpg", so I renamed the albumcover.jpg to folder jpg.
The results for these two actions were:
a) The album/CD cover was available for the Music App
b) The album/CD cover no longer appeared in the Gallery
I have 5 gb of music on my SD card so I completed the job by connecting my Droid to the PC, turned on USB storage and used the PC's file explorer to perform the above steps. On the PC, in File Explorer, I had to go to Tool/Folder options/Viwe and ensure that the box "Show hidden files and folders" was selected and that the box for "Hide protected operating system files" was unchecked.
For each album, I did the following as needed:
1. If there was no folder.jpg, renamed the file for the album/cd cover to folder.jpg and deleted all other album/cd cover files
2a. If there was a "folder.jpg", I viewed it to ensure it was the album cover, if not, I deleted it and renamed the "albumcover".jpg to "folder.jpg and deleted all other album/cd cover files.
2b. If there was a "folder.jpg", I viewed it to ensure it was the album cover, if was the album.CD cover, I deleted all other album/cd cover files.
When I finished, I reset the File Explorer options back to what they were.
Now, I have no album covers in the Gallery.