I exported the images following the doc: https://www.electron.build/configuration/appx.html#appx-assets.
4 required images are used:
Logo: StoreLogo.png
Square150x150Logo: Square150x150Logo.png
Square44x44Logo: Square44x44Logo.png
Wide310x150Logo: Wide310x150Logo.png
However the installed app icon is not taking up all icon background area leaving a black background: