Cannot manually add artwork to fuze core

I’m really struggling with Box Art for the zx Specturm (fuse ) Core. I’ve scanned for the playlist and that listed all the roms updated thumbnails, but it only downloads about five box art images. I’ve tried manually adding box art to the correct folder, making sure the title is identical to the rom, but is never shows up. The few box art that retroarch downloads does show up, strangely though, some of them do not have an identical title as the rom it’s associated to, but still shows up!! I’m I missing a step, is there something I should do in retroarch after I have Manually added artwork? Also I though about looking the playlist .LPL, but when I do it’s just a series of black diamond symbols, I guess I need some for of reader? Screenshot added to help Any help would be great Cheers A (edited)