问题比较简单，直接上代码.

    private Image _Cover;

        [Size(SizeAttribute.Unlimited), ValueConverter(typeof(ImageValueConverter))]

        public Image Cover

        {

            get

            {

                if (_Cover == null && _Photo != null && _Photo.Length > 0)

                {

                    using (MemoryStream stream = new System.IO.MemoryStream(_Photo))

                    {

                        System.Drawing.Image image = System.Drawing.Image.FromStream(stream);

                        _Cover = image;

                        return _Cover;

                    }

                }

                return _Cover;

            }

            set

            {

                SetPropertyValue("Cover", ref _Cover, value);

            }

        }

        private Byte[] _Photo;

        //[Delayed]

        public Byte[] Photo

        {

            get

            {

                return _Photo;

            }

            set

            {

                //byte[] imagedata = null;

                //if (Cover != null)

                //{

                //    MemoryStream ms = new MemoryStream();

                //    Image im = new Bitmap(Cover);

                //    im.Save(ms, System.Drawing.Imaging.ImageFormat.Jpeg);

                //    imagedata = ms.GetBuffer();

                //    _Photo = imagedata;

                //}

                SetPropertyValue("Photo", ref _Photo, value);

            }

        }

   Image fPhoto;

        [ValueConverter(typeof(ImageValueConverter)), Delayed]

        public Image Photo

        {

            get { return fPhoto; }

            set { SetPropertyValue("Photo", ref fPhoto, value); }

        }