How to attach image files to Music files in iTunes?
How does one attach, say a jpeg or png file, to an existing mp3 / wav / aac / whatever music file happens to be present for use in iTunes and other places?
I have a vague memory of having done it in the distant past but can't seem to recall the steps...
[Re-Titled By Moderator]
MacBook Pro 13″, macOS 10.14