You will need to zip the bezel file (the image and (I have) a bezel.lay file) that is then placed in the same folder as the marquee, header, logo files, etc... inside the named game folder in the assets folder.
Windows(C: )>users>Polycade(user installed under)>Appdata>Roaming>Polycade>Assets>Arcade>game folder
Things to know:
The "Windows(C: )" for the drive could be different on yours as well.
Users folder would be what your polycade is installed under. Mine is Polycade
I believe you can only do bezels on Mame games so the folder in the Assets folder will be "Arcade"
The zip folder for the bezel must be named the same as the rom for the game.
You will need to adjust positions and game screen size within the bezel in the .lay file. The .lay file must reference the bezel name at the top to work. This is why I name all mine, bezel_day. To keep from having to change it.
The first level of the game assets folder might look like this:
Header image
Hero image
logo image
marquee image (if digital marquee)
game name.zip folder
The gamename.zip folder will look like this:
game name folder
DefaultBezel.png
Inside the game name folder:
artwork folder
game name.ini file
Inside the artwork folder:
bezel.png
bezel.psd (I have a copy of my photoshop file in mine)
default.lay
Hope this helps... questions let me know and if I left anything out others please chime in.
Thanks!