The image not fill all toggle space

[caokietbk]

Describe the bug
A clear and concise description of what the bug is.

To Reproduce
Steps to reproduce the behavior:

1. create the switch with active icon = Image.asset.
2. change toggleColor: Colors.red (to make it more visible)
3. See error

Expected behavior
The image should be filled and have a fixed height and width (no red color).

Screenshots

Smartphone (please complete the following information):

• Device: iPhone Xr
• OS: iOS15

Additional context
Source code:

return FlutterSwitch(
      value: _currentValue,
      onToggle: (newValue) {
        setState(() {
          _currentValue = newValue;
        });
      },
      height: 30,
      activeIcon: Image.asset(
        'slider-thumb'.pngAssetsPath,
        height: 30,
      ),
      inactiveIcon: Image.asset(
        'slider-thumb'.pngAssetsPath,
        height: 30,
      ),
      toggleColor: Colors.red,
      activeColor: CustomColors.greenIndicator,
      inactiveColor: CustomColors.pinkIndicator,
);

Thanks