Hi, I have experience implementing checkbox using a toggle as it looks awkward, meaning doesn't blend in with other controls, when I use checked and unchecked images.
Added below to "Advanced Presentation Options" of checkbox cell property.
right-aligned phone ios-slider
Whenever you need to show in read-only mode, I used an "image" control and set to use Icon Class to use pi-box-check. I found it much easier to change size, color, animate, etc. using css, compared to using checkbox image where you need to edit the image itself and upload whenever you need different version of checkbox image.