ImageGen sample implementation

ImageUrlProvider.cs

namespace UmbImageDemo
{
	public class ImageUrlProvider : IImageUrlProvider
	{
		public string Name
		{
			get { return "imageGen"; }
		}

		public string GetImageUrlFromMedia(int mediaId, IDictionary<string, string> parameters)
		{
			string url = string.Empty;
			var nodeIterator = library.GetMedia(mediaId, false);
			if (nodeIterator.Current != null)
			{
				var filename = getProperty(nodeIterator, "umbracoFile");
				url = withParams(filename, parameters);
			}

			return url;
		}

		public string GetImageUrlFromFileName(string specifiedSrc, IDictionary<string, string> parameters)
		{
			return withParams(specifiedSrc, parameters);
		}

		private string withParams(string filename, IDictionary<string, string> parameters)
		{
			string urlParams = String.Join("&", parameters.Keys.Select(k => String.Join("=", k, parameters[k])));
			return string.Format("/ImageGen.ashx?image={0}&{1}", filename, urlParams);
		}

		private static string getProperty(XPathNodeIterator nodeIterator, string fileProp)
		{
			string xpath = UmbracoSettings.UseLegacyXmlSchema
							   ? string.Format(".//data[@alias = '{0}']", fileProp)
							   : string.Format(".//{0}", fileProp);
			var file = nodeIterator.Current.SelectSingleNode(xpath).InnerXml;
			return file;
		}

	}
}