Array Shuffle Exgtension

namespace Test
{
    public class Test : MonoBehaviour
    {
        // Change this to your Images.
        public string [ ] ImageNames = { "One", "Two", "Three", "Four" };
        private int [ ] order;

        private void Awake ( )
        {
            var count = ImageNames.Length;

            // Create an order array that we will shuffle, leaving the original array intact.
            order = new int [ ImageNames.Length ];
            for ( int i = 0; i < count; i++ )
                order [ i ] = i;

            // Shuffle the order array, so that you can then select the right Images.
            // This order array now holds a reference to the original Image array.
            order.Shuffle ( );

            // Demonstrate that the order has been shuffled.
            System.Text.StringBuilder sb = new System.Text.StringBuilder ( );
            for ( int i = 0; i < order.Length; i++ )
            {
                sb.Append ( ImageNames [ order[i] ] );
                if ( i < order.Length - 1 )
                    sb.Append ( ", " );
            }
            Debug.Log ( sb.ToString ( ) );
        }
    }

    public static class ArrayExtension
    {
        private static readonly System.Random rng = new System.Random ( );
        public static void Shuffle<T> ( this T [ ] array )
        {
            int n = array.Length;
            while ( n > 1 )
            {
                n--;
                int k = rng.Next ( n + 1 );
                T value = array [ k ];
                array [ k ] = array [ n ];
                array [ n ] = value;

            }
        }
    }
}