Exporting rekordbox artwork to USB

So I have my rekordbox library on my mac, + I have it on 2x USB sticks for playing out on cdjs.

I have recently used software to embed artwork to all of my music files on my mac and they all display on the collection part of rekordbox.

I have synced over the data to my USB stick. It has added all of the new data (tags etc) , except it hasnt added the artwork.

How can I get the artwork to update on the USB stick? To clarify, its all there on the collection tab.