How to add photo to .mp3 file.
I am trying to add a photo to my group of .mp3 files and have been able to do it through iTunes but the images don't show up in my finder, and only on iTunes. I tried the suggestions from a similar 2011 post with no results. I'm assuming it's due to an interface change between then and now. Can anyone help? I also tried copying & pasting different image files (.png, .jpg) onto the 'Get Info' page for each .mp3 file with no luck.
MacBook Air 13″, macOS 10.12