I figured it out, the issue I was having is I had imported many of my mame games using the USA rom and not the standard/parent EUR roms. The way it finds and matches up the cab art is by using the name of the rom or game executable and since many of my roms had a u at the end for USA they weren't being picked up. So mvsc is what the cab art was labeled but my imported rom was mvscu, once I renamed the art .png's they were picked up right away.