Use LINQ to parse image query results from Google, Bing, and Yahoo search engines.

BingImageQuery.cs

namespace SilverShorts
{
   /// <summary>
   /// Implement a Microsoft Bing IImageQuery provider
   /// </summary>
   public class BingImageQuery : IImageQuery
   {
      /// <summary>
      /// Bing Image Query requires a valid ApiKey
      /// See: http://www.bing.com/developer/
      /// </summary>
      public bool RequiresApiKey { get { return true; } }

      public string FormatQueryUrl(string search, string appId, int numImages, int offset, bool useSafeSearch)
      {
         return "http://api.bing.net/xml.aspx?"
             + "AppId=" + appId
             + "&Query=" + search
             + "&Sources=Image"
             + "&Version=2.0"
             + "&Market=en-us"
             + (useSafeSearch ? "&Adult=Moderate" : "")
             + "&Image.Count=" + numImages.ToString()
             + "&Image.Offset=" + offset.ToString();
      }

      public void ProcessResultString(string response, List<ImageResult> results)
      {
         // Parse the XML response text 
         XDocument doc = XDocument.Parse(response);

         // Elements in the response all conform to this schema and have a namespace prefix of mms:
         // For our LINQ query to work properly, we must use mmsNs + ElementName
         XNamespace mmsNs = XNamespace.Get("http://schemas.microsoft.com/LiveSearch/2008/04/XML/multimedia");

         // Build a LINQ query to parse the XML data into our custom ImageResult objects
         var imageResults =
            from ir in doc.Descendants()
            where ir.Name.Equals(mmsNs + "ImageResult")
            select new ImageResult()
            {
               Title = ir.Element(mmsNs + "Title").Value,
               MediaUrl = ir.Element(mmsNs + "MediaUrl").Value,
               Url = ir.Element(mmsNs + "Url").Value,
               DisplayUrl = ir.Element(mmsNs + "DisplayUrl").Value,
               Width = Int32.Parse(ir.Element(mmsNs + "Width").Value),
               Height = Int32.Parse(ir.Element(mmsNs + "Height").Value),

               Thumb =
                  (from th in ir.Descendants()
                   where th.Name.Equals(mmsNs + "Thumbnail")
                   select new ImageResult.Thumbnail()
                   {
                      Url = th.Element(mmsNs + "Url").Value,
                      Width = Int32.Parse(th.Element(mmsNs + "Width").Value),
                      Height = Int32.Parse(th.Element(mmsNs + "Height").Value),
                   }).Single(),
            };


         // Execute the LINQ query and stuff the results into our list 
         results.AddRange(imageResults);
      }
   }
}

GoogleImageQuery.cs

namespace SilverShorts
{
   /// <summary>
   /// Implement a Google IImageQuery provider using AJAX api and JSON.Net
   /// See: http://code.google.com/apis/ajaxsearch/documentation/reference.html#_intro_fonje
   /// </summary>
   public class GoogleImageQuery : IImageQuery
   {
      /// <summary>
      /// Google Image Query does not require (but strongly recommends) a valid ApiKey
      /// </summary>
      public bool RequiresApiKey { get { return false; } }

      public string FormatQueryUrl(string search, string appId, int numImages, int offset, bool useSafeSearch)
      {
         return "http://ajax.googleapis.com/ajax/services/search/images?v=1.0"
             + "&q=" + search
             + "&key=" + appId
             + (useSafeSearch ? "&safe=m" : "")
             + "&start=" + Convert.ToString(offset);
      }

      public void ProcessResultString(string response, List<ImageResult> results)
      {
         // Parse the JSON string
         JObject json = JObject.Parse(response);

         // Check response validity, throw exception with details if error
         if ((int)json["responseStatus"] != 200)
            throw new Exception((string)json["responseDetails"]);

         // Parse out results using LINQ
         var imageResults =
            from ir in json["responseData"]["results"].Children()
            where ((string)ir["GsearchResultClass"]).Equals("GimageSearch")
            select new ImageResult()
            {
               Title = (string)ir["title"],
               MediaUrl = (string)ir["unescapedUrl"],
               Url = (string)ir["url"],
               DisplayUrl = (string)ir["visibleUrl"],
               Width = Int32.Parse((string)ir["width"]),
               Height = Int32.Parse((string)ir["height"]),
               Thumb = new ImageResult.Thumbnail()
               {
                  Url = (string)ir["tbUrl"],
                  Width = Int32.Parse((string)ir["tbWidth"]),
                  Height = Int32.Parse((string)ir["tbHeight"]),
               }
            };

         // Execute the LINQ query and stuff the results into our list 
         results.AddRange(imageResults);
      }
   }
}

WebImageQuery.cs

namespace SilverShorts
{
   public class WebImageQuery
   {
      /// <summary>
      /// Construct a WebImageQuery using the specified IImageQuery provider 
      /// </summary>
      public WebImageQuery(IImageQuery provider) { _queryProvider = provider; }
      private WebImageQuery() { }

      private IImageQuery _queryProvider;

      /// <summary>
      /// Specifies the API specific key (if any) for the search provider
      /// </summary>
      private string _apiKey;
      public string ApiKey
      {
         get { return _apiKey; }
         set { _apiKey = value; }
      }

      /// <summary>
      /// Delegate for Completed query event handlers
      /// </summary>
      /// <param name="results"></param>
      public delegate void QueryCompletedEventHandler(List<ImageResult> results);
      
      /// <summary>
      /// Fired when the asynchronous web image query is complete
      /// </summary>
      public event QueryCompletedEventHandler QueryCompleted;

      /// <summary>
      /// 
      /// </summary>
      /// <param name="search"></param>
      /// <param name="callback"></param>
      /// <param name="numImages"></param>
      /// <param name="offset"></param>
      /// <param name="useSafeSearch"></param>
      public void Search(string search, int numImages = 10, int offset = 0, bool useSafeSearch = true)
      {
         if (_queryProvider == null)
            throw new ArgumentNullException("_queryProvider");

         if (_queryProvider.RequiresApiKey && string.IsNullOrEmpty(_apiKey))
            throw new ArgumentNullException("ApiKey", "This search provider requires a valid key");

         string requestString = _queryProvider.FormatQueryUrl(search, _apiKey,numImages, offset, useSafeSearch);

         WebClient client = new WebClient();
         client.DownloadStringCompleted += _downloadStringCompleted;
         client.DownloadStringAsync(new Uri(requestString, UriKind.Absolute));
      }

      /// <summary>
      /// WebClient DownloadStringAsync Event handler
      /// </summary>
      /// <param name="e">e.UserState as SearchResultCallback</param>
      private void _downloadStringCompleted(object sender, DownloadStringCompletedEventArgs e)
      {
         if (_queryProvider == null)
            throw new ArgumentNullException("_queryProvider");

         if (e.Error != null)
            return;

         List<ImageResult> results = new List<ImageResult>();
         try
         {
            _queryProvider.ProcessResultString(e.Result.ToString(), results);
         }
         catch (System.Exception ex)
         {
            throw new Exception("Failed Process Image Query Result", ex);
         }

         // QueryCompleted event
         if (QueryCompleted != null)
            QueryCompleted(results);
      }
   }
}

YahooImageQuery.cs

namespace SilverShorts
{
   /// <summary>
   /// Implement a Yahoo Image Search IImageQuery provider
   /// </summary>
   public class YahooImageQuery : IImageQuery
   {
      /// <summary>
      /// Yahoo Image Query requires a valid ApiKey
      /// See: https://developer.apps.yahoo.com/projects
      /// </summary>
      public bool RequiresApiKey { get { return true; } }

      public string FormatQueryUrl(string search, string apiKey, int numImages, int offset, bool useSafeSearch)
      {
         return "http://search.yahooapis.com/ImageSearchService/V1/imageSearch?"
          + "appid=" + apiKey
          + "&query=" + search
          + "&results=" + numImages
          + "&start=" + offset
          + (useSafeSearch ? "" : "&adult_ok=1");
      }

      public void ProcessResultString(string response, List<ImageResult> results)
      {
         // Parse the XML response text 
         XDocument doc = XDocument.Parse(response);
         XNamespace yahNs = "urn:yahoo:srchmi";
         
         // Build a LINQ query to parse the XML data into our custom ImageResult objects
         var imageResults =
            from ir in doc.Descendants()
            where ir.Name.Equals(yahNs + "Result")
            select new ImageResult()
            {
               Title = ir.Element(yahNs + "Title").Value,
               MediaUrl = ir.Element(yahNs + "ClickUrl").Value,
               Url = ir.Element(yahNs + "Url").Value,
               DisplayUrl = ir.Element(yahNs + "RefererUrl").Value,
               Width = Int32.Parse(ir.Element(yahNs + "Width").Value),
               Height = Int32.Parse(ir.Element(yahNs + "Height").Value),

               Thumb =
                  (from th in ir.Descendants()
                   where th.Name.Equals(yahNs + "Thumbnail")
                   select new ImageResult.Thumbnail()
                   {
                      Url = th.Element(yahNs + "Url").Value,
                      Width = Int32.Parse(th.Element(yahNs + "Width").Value),
                      Height = Int32.Parse(th.Element(yahNs + "Height").Value),
                   }).Single(),
            };


         // Execute the LINQ query and stuff the results into our list 
         results.AddRange(imageResults);
      }
   }
}