/// <summary>
        /// Add the settings from "PictureTag" of the appsettings as a Singleton of PictureTagOptions
        /// </summary>
        /// <param name="services">Specifies the contract for a collection of service descriptors.</param>
        /// <param name="configuration">Represents the root of an IConfiguration hierarchy.</param>
        /// <returns>IServiceCollection</returns>
        public static IServiceCollection AddPictureTagSettings(
            this IServiceCollection services,
            PictureTagOptions settings
            )
        {
            services.AddSingleton(settings);

            return(services);
        }
        public PictureTagHelper(
            PictureTagOptions options
            )
        {
            if (options == null)
            {
                throw new ArgumentNullException(nameof(options));
            }

            this.options = options;
        }
        /// <summary>
        /// Add the settings from "PictureTag" of the appsettings as a Singleton of PictureTagOptions
        /// </summary>
        /// <param name="services">Specifies the contract for a collection of service descriptors.</param>
        /// <param name="configuration">Represents the root of an IConfiguration hierarchy.</param>
        /// <returns>IServiceCollection</returns>
        public static IServiceCollection AddPictureTagSettings(
            this IServiceCollection services,
            IConfiguration configuration
            )
        {
            var section  = configuration.GetSection("PictureTag");
            var settings = new PictureTagOptions();

            new ConfigureFromConfigurationOptions <PictureTagOptions>(section)
            .Configure(settings);
            services.AddSingleton(settings);

            return(services);
        }