Treats provided images like a template

[BenderNK]

I love the idea and documentation of this library. Unfortunately, it didn't work for me as it appears that this library is treating the custom checkbox images as though they were templates.

Here is my setup:
XCode 13.3
macOS 12.3.1

Configuration

Resulting on and off state

However, when using SF symbols, it appears to be working as expected. See configuration:

SF Symbols Configuration

Resulting on and off state