Cover Art with Join files with MP4Box.kmmacros?

I've been using Tom's great shortcut to MP4Box for months and would be lost without it. Does anyone know if there's a convention for naming cover art so it will recognize a .jpg and apply it to the generated m4a?

You mean as a file icon?

You can set a file icon with Keyboard Maestro, although I'm not sure how well it handles oddball aspect ratios...


I remember seeing a macro that adds padding to images, to create a square one getting its Local__Width and Local__Height