Bitmap Memory Problem

I've got a video capture program I'm developing that captures images (1920 X 1080)
And I'm trying to kill a memory usage issue, after taking a few dozen images I can have a memory usage of over 1.5G in the task manager.

Now I've got a simplified version (that also has the memory issue)

(Code Also Attached)
ImageCreation.cs


using System.Drawing;

using System.Drawing.Imaging;

namespace VidMemLeakDebug

{

    class ImageCreation

    {

        public static Bitmap GiveMeAnImage()

        {

            Bitmap ImageToReturn = new Bitmap(1920, 1080, PixelFormat.Format16bppRgb565);

            return ImageToReturn;

        }

    }

}

Form1.CS


using System;

using System.Drawing;

using System.Drawing.Imaging;

using System.Windows.Forms;


namespace VidMemLeakDebug

{

    public partial class Form1 : Form

    {

        private static Bitmap MyStaticUpImage = new Bitmap(1920, 1080, PixelFormat.Format16bppRgb565);

        private static Bitmap MyStaticDownImage = new Bitmap(1920, 1080, PixelFormat.Format16bppRgb565);

        public Form1()

        {

            InitializeComponent();

        }


        private void button1_Click(object sender, EventArgs e)

        {

            using (Bitmap TempBitmap = ImageCreation.GiveMeAnImage())

            {

                MyStaticUpImage = new Bitmap(TempBitmap);

            }

        }


        private void button2_Click(object sender, EventArgs e)

        {

            MyStaticDownImage.Save("JunkUpImage.bmp");

            MyStaticUpImage.Save("JunkUpImage.bmp");

        }


        private void button3_Click(object sender, EventArgs e)

        {

            using (Bitmap TempBitmap = ImageCreation.GiveMeAnImage())

            {

                MyStaticDownImage = new Bitmap(TempBitmap);

            }


        }


    }

}

How the program works.
The user might need to take dozens of Up and Or Down images before they have a valid set that can be save, so each image from the ImageCreation.GiveMeAnImage() is stored in a local static Bitmap (Either UpImage or DownImage) depending on what button they push.

Then when they are stratified, they can save the image pair.

now when I first start I'm getting about 15Mem Memory Usage ( ImageUp & ImageDown are created at startup)
But when I take each "picture" the memory jumps by about 8-9 Meg, and never comes down (I thought the Using(){} was supposed to clean that up)

How can I copy my temporary Image (from GiveMeAnImage) to my Static Image Buffers without having it recreate a new buffer each time?