private void DeletePortfolioImage(DbObjects.Business.PortfolioImage image)
        {
            string absolutePath = Server.MapPath(image.ImageUrl);

            //delete physical image file
            if (File.Exists(absolutePath))
            {
                File.Delete(absolutePath);
            }

            //remove image from database
            SelectedPortfolioCategory.RemoveImage(image.Id);
        }