Object is currently in use elswhere

The following method keeps on generating an exception about the object being currently in use elsewhere.

public void testMethod(int imageNum)
{
imageOne = new Bitmap(50, 50);
panelB.DrawToBitmap(imageOne, new Rectangle(0, 0, 50,50));
imageOne.Save("H:\\" + imageNum + ".bmp", ImageFormat.Bmp);
panelA.BackgroundImage = imageOne;
imageTwo = myMethod();
panelB.BackgroundImage = imageTwo;
}

Here is the exception and StackTrace.

A first chance exception of type 'System.AccessViolationException' occurred in System.Drawing.dll
A first chance exception of type 'System.InvalidOperationException' occurred in System.Drawing.dll
Message: Object is currently in use elsewhere.
TargetSite: Int32 get_Flags()
Source: System.Drawing
InnerException: 
StackTrace:    at System.Drawing.Image.get_Flags()
   at System.Windows.Forms.ControlPaint.IsImageTransparent(Image backgroundImage)
   at System.Windows.Forms.Control.PaintBackground(PaintEventArgs e, Rectangle rectangle, Color backColor, Point scrollOffset)
   at System.Windows.Forms.Control.PaintBackground(PaintEventArgs e, Rectangle rectangle)
   at System.Windows.Forms.Control.OnPaintBackground(PaintEventArgs pevent)
   at System.Windows.Forms.ScrollableControl.OnPaintBackground(PaintEventArgs e)
   at System.Windows.Forms.Control.PaintWithErrorHandling(PaintEventArgs e, Int16 layer)
   at System.Windows.Forms.Control.OnPrint(PaintEventArgs e)
   at System.Windows.Forms.Control.WmPrintClient(Message& m)
   at System.Windows.Forms.Control.WndProc(Message& m)
   at System.Windows.Forms.ScrollableControl.WndProc(Message& m)
   at System.Windows.Forms.Control.ControlNativeWindow.OnMessage(Message& m)
   at System.Windows.Forms.Control.ControlNativeWindow.WndProc(Message& m)
   at System.Windows.Forms.NativeWindow.DebuggableCallback(IntPtr hWnd, Int32 msg, IntPtr wparam, IntPtr lparam)
   at System.Windows.Forms.UnsafeNativeMethods.CallWindowProc(IntPtr wndProc, IntPtr hWnd, Int32 msg, IntPtr wParam, IntPtr lParam)
   at System.Windows.Forms.NativeWindow.DefWndProc(Message& m)
   at System.Windows.Forms.Control.DefWndProc(Message& m)
   at System.Windows.Forms.Control.WndProc(Message& m)
   at System.Windows.Forms.ScrollableControl.WndProc(Message& m)
   at System.Windows.Forms.Control.ControlNativeWindow.OnMessage(Message& m)
   at System.Windows.Forms.Control.ControlNativeWindow.WndProc(Message& m)
   at System.Windows.Forms.NativeWindow.DebuggableCallback(IntPtr hWnd, Int32 msg, IntPtr wparam, IntPtr lparam)
   at System.Windows.Forms.UnsafeNativeMethods.SendMessage(HandleRef hWnd, Int32 msg, IntPtr wParam, IntPtr lParam)
   at System.Windows.Forms.Control.DrawToBitmap(Bitmap bitmap, Rectangle targetBounds)
   at Testing.Test.testMethod(Int32 imageNum) in Test.cs:line 72

Not sure how to solve the problem. Please help!