Using image in Pictures Libraries

My app admin store some imagepath using the image in Pictures Libraries. When the user want to see the the image that the admin store how do I do that in the datasource ?

This is the default code:

private static Uri _baseUri = new Uri("ms-appx:///");

private ImageSource _image = null;
        private String _imagePath = null;

        public ImageSource Image
        {
            get
            {
                if (this._image == null && this._imagePath != null)
                {
                    this._image = new BitmapImage(new Uri(VMDataCommon._baseUri, this._imagePath));
                }
                return this._image;
            }

            set
            {
                this._imagePath = null;
                this.SetProperty(ref this._image, value);
            }
        }

        public void SetImage(String path)
        {
            this._image = null;
            this._imagePath = path;
            this.OnPropertyChanged("Image");
        }

I know that the baseURI is for local app data but I don't know to change to Libraries Pictures. I seen some example from this sites but don't understand.

http://stackoverflow.com/questions/12235026/metro-windows-8-c-xaml-how-to-find-valid-uris-to-pictures-stored-in-the-docu

Thanks.

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Thanks, Smiths