How to insert album cover art on music files?


I have searched the net for answers and I have not found any feasible answer to the question:
"How to insert album cover art on music files?"

I have about 4-6TB of music on external hard drives. Much of this music came from live broadcast sources through the years. I also have much HR music recorded from various on line services recorded via a HR Tascam recorder then transferred to the hard drive.
How can I insert a picture into those music files on my hard drive? Low rez sources such as iTunes, or mp3 conversion is not an option.

ozzy
128x128ozzy
Mp3tag will tag most any audio files. WAV is system dependant on whether it will show up.
I only wish that Florian made a version for photos.
I use the music file editor that comes with dbpoweramp to Manually fix tags and art as needed.  Just right click on the files and tag and add artwork as needed. 
In most cases dbpoweramp does a good job of adding cover art at rip time.   If not then O use Picard software which is pretty good at auto tagging and adding art.  I Only use manual dbpoweramp editor as a last resort,  often when converting from vinyl where auto tagging tends to not work as well. 
Do any of these cost money to download?
And I already have the music on the hard drive and most are in the wav format.
ozzy
Picard can be downloaded for free. Very powerful and able to auto tag and add album art automatically in many cases.

if you already own and rip using dbpoweramp the editor is included.  Otherwise a nominal cost to download.