Here's a little app I've built using batch script and powershell alone. All the code is unobfuscated and can be read and modified easily to make any type of icon if you know what youre doing.
Drop a background and logo into the main folder. Background can be jpeg or png, and any aspect ratio or resolution (recommended at least 720p to look good on TV), the script handles conversion to jpeg and cropping from centre to make it 16:9. Logo must be png, but can be any resolution (recommended 512p) and aspect ratio, the script handles making the logo square ready for using in your app.
Drop a background and logo into the main folder. Background can be jpeg or png, and any aspect ratio or resolution (recommended at least 720p to look good on TV), the script handles conversion to jpeg and cropping from centre to make it 16:9. Logo must be png, but can be any resolution (recommended 512p) and aspect ratio, the script handles making the logo square ready for using in your app.