Hi,
 Please find the code....
using System;
using System.Drawing;
using System.Runtime.InteropServices;
using ESRI.ArcGIS.ADF.BaseClasses;
using ESRI.ArcGIS.ADF.CATIDs;
using ESRI.ArcGIS.Framework;
using ESRI.ArcGIS.ArcMapUI;
namespace CountPoints
{
    /// <summary>
    /// Summary description for InsertPic.
    /// </summary>
    [Guid("b311d914-e999-4014-8bcb-2cef2da34b71")]
    [ClassInterface(ClassInterfaceType.None)]
    [ProgId("CountPoints.InsertPic")]
    public sealed class InsertPic : BaseCommand
    {
        #region COM Registration Function(s)
        [ComRegisterFunction()]
        [ComVisible(false)]
        static void RegisterFunction(Type registerType)
        {
            // Required for ArcGIS Component Category Registrar support
            ArcGISCategoryRegistration(registerType);
            //
            // TODO: Add any COM registration code here
            //
        }
        [ComUnregisterFunction()]
        [ComVisible(false)]
        static void UnregisterFunction(Type registerType)
        {
            // Required for ArcGIS Component Category Registrar support
            ArcGISCategoryUnregistration(registerType);
            //
            // TODO: Add any COM unregistration code here
            //
        }
        #region ArcGIS Component Category Registrar generated code
        /// <summary>
        /// Required method for ArcGIS Component Category registration -
        /// Do not modify the contents of this method with the code editor.
        /// </summary>
        private static void ArcGISCategoryRegistration(Type registerType)
        {
            string regKey = string.Format("HKEY_CLASSES_ROOT\\CLSID\\{{{0}}}", registerType.GUID);
            MxCommands.Register(regKey);
        }
        /// <summary>
        /// Required method for ArcGIS Component Category unregistration -
        /// Do not modify the contents of this method with the code editor.
        /// </summary>
        private static void ArcGISCategoryUnregistration(Type registerType)
        {
            string regKey = string.Format("HKEY_CLASSES_ROOT\\CLSID\\{{{0}}}", registerType.GUID);
            MxCommands.Unregister(regKey);
        }
        #endregion
        #endregion
        private IApplication m_application;
        public InsertPic()
        {
            //
            // TODO: Define values for the public properties
            //
            base.m_category = "PageLayout"; //localizable text
            base.m_caption = "Insert Pic";  //localizable text
            base.m_message = "Insert Picture into Pagelayout";  //localizable text 
            base.m_toolTip = "Insert Picture into Pagelayout";  //localizable text 
            base.m_name = "Insert_pic";   //unique id, non-localizable (e.g. "MyCategory_ArcMapCommand")
            try
            {
                //
                // TODO: change bitmap name if necessary
                //
                string bitmapResourceName = GetType().Name + ".bmp";
                base.m_bitmap = new Bitmap(GetType(), bitmapResourceName);
            }
            catch (Exception ex)
            {
                System.Diagnostics.Trace.WriteLine(ex.Message, "Invalid Bitmap");
            }
        }
        #region Overriden Class Methods
        /// <summary>
        /// Occurs when this command is created
        /// </summary>
        /// <param name="hook">Instance of the application</param>
        public override void OnCreate(object hook)
        {
            if (hook == null)
                return;
            m_application = hook as IApplication;
            //Disable if it is not ArcMap
            if (hook is IMxApplication)
                base.m_enabled = true;
            else
                base.m_enabled = false;
            // TODO:  Add other initialization code
        }
        /// <summary>
        /// Occurs when this command is clicked
        /// </summary>
        public override void OnClick()
        {
            // TODO: Add InsertPic.OnClick implementation
            IMxDocument pMxDoc = m_application.Document as IMxDocument;
            ESRI.ArcGIS.Carto.IPictureElement pPictureElement;
            pPictureElement = new ESRI.ArcGIS.Carto.JpgPictureElementClass();
            pPictureElement.ImportPictureFromFile(@"D:\PROJECTS\MyProject\Images\Excel2.jpg");
            ESRI.ArcGIS.Geometry.IEnvelope pEnv = new ESRI.ArcGIS.Geometry.EnvelopeClass();
            pEnv.PutCoords(1, 1, 5, 5);
            ESRI.ArcGIS.Carto.IElement pElement;
            pElement = pPictureElement as ESRI.ArcGIS.Carto.IElement;
            pElement.Geometry = pEnv;
            ESRI.ArcGIS.Carto.IGraphicsContainer pGraphicContainer;
            pGraphicContainer = pMxDoc.PageLayout as ESRI.ArcGIS.Carto.IGraphicsContainer;
            pGraphicContainer.AddElement(pElement, 0);
            ESRI.ArcGIS.Carto.IActiveView pActiveView;
            pActiveView = pGraphicContainer as ESRI.ArcGIS.Carto.IActiveView;
            pActiveView.PartialRefresh(ESRI.ArcGIS.Carto.esriViewDrawPhase.esriViewGraphics, pElement, pEnv);
        }
        #endregion
    }
}
I hope this helps you...
Thanks and Regards,
Venkat