BingImageSearch.cs

 static async void FindAndRetrieveImage()
        {
            var client = new HttpClient();
            var queryString = HttpUtility.ParseQueryString(string.Empty);

            // Request headers
            client.DefaultRequestHeaders.Add("Ocp-Apim-Subscription-Key", <AppId Goes Here>);

            // Request parameters
            queryString["q"] = string.Format("{0}", "grumpy cat");
            queryString["count"] = "10";
            queryString["offset"] = "0";
            queryString["mkt"] = "en-us";
            queryString["safeSearch"] = "Moderate";
            queryString["size"] = "large";
            //queryString["color"] = "Green";
            //queryString["imageContent"] = "Face";

            var uri = "https://api.cognitive.microsoft.com/bing/v5.0/images/search?" + queryString;

            // Make the query
            var response = await client.GetAsync(uri);
            string content = await response.Content.ReadAsStringAsync();

            // Fabricate a quick anonymous type and deserialize to it
            var responseType = new { value = new[] { new { contentUrl = "", width = 0, height = 0 } } };
            var results = JsonConvert.DeserializeAnonymousType(content, responseType);

            // Grab results you want
            var firstResult = results.value.First().contentUrl;

            // Download the image
            WebClient webClient = new WebClient();
            using (var imageStream = new MemoryStream(webClient.DownloadData(firstResult)))
            {
                Image image = Image.FromStream(imageStream);

                // Make any adjustments to size/format/etc here

                image.Save("image.jpg", ImageFormat.Jpeg);
            }
                
        }