For Example I have two folders:
Kura - Skank
Hardwell - Spaceman
they both have a cover art image in them but its not embedded into the mp3
I want to automatically embed every image to every file in that respective folder?
there is an action for that: Import cover from file.
You can enter a string constant as filename like folder.jpg or cover.jpg or a string with wildcards like *.jpg which takes the first picture file that is found.
Or you enter a format string like %album%.jpg if the file is named like the album.
If you use the wildcards then MP3tag uses the first picture that the OS returns. So it is a little random.
Pictures are embedded for all the selected files, the search always starts in the directory of the current file.