Here is a link to the box art for the NEO GEO Arcade:
https://drive.google.com/open?id=1bBtNhXk-sayHJbl1DNFXHyoxhLyCz_a0
Here are some examples in the pack:
To add the box art to the games:
1. Add them to the SD card. I put mine in a NEOGEO folder I created in the Media Folder.
2. Choose the "NEOGEO" emulator from the menu and click the 'Select' button.
3. Select "Edit NEOGEO" and scroll down to the Box Art option and click 'A'
4. Navigate to the NEOGEO folder you put the Box Art in and click the 'Start' button to exit.
The cover art image files have to match the rom name exactly or they won't show up.