Getting all the non active toggles in a toggle Group .

Questions & Answers
1

As it says I want to change image of all the toggle button back to default except for the active one , so i need a method which would get me all the non active toggles.
Thank you.

2

Make sure each toggle is attached to a child object of the toggle group object. That is, there should be one game object in your hierarchy with a ToggleGroup component, and the only Toggles in that ToggleGroup are attached to children of that game object.

From here, you can add a method to CustomScript that returns all inactive toggles

List<Toggle> InactiveToggles()
{
    // get all toggles, active and inactive
    List<Toggle> toggles = GetComponentsInChildren<Toggle>();

    // find the active toggle and remove it
    foreach(Toggle toggle in toggles)
    {
        if(toggle.isOn) 
        {
            toggles.Remove(toggle);
            return toggle; // only at most one toggle will be on
    }
    return toggles; // no toggles were on
}

Hope this helps!