Download Image from the Site in .Net/C#

How to download image from URL

Simply
You can use following methods.

using (WebClient client = new WebClient()) 
{
    client.DownloadFile(new Uri(url), @"c:\temp\image35.png");
    // OR 
    client.DownloadFileAsync(new Uri(url), @"c:\temp\image35.png");
}

These methods are almost same as DownloadString(..) and DownloadStringAsync(...). They store the file in Directory rather than in C# string and no need of Format extension in URi

If You don't know the Format(.png, .jpeg etc) of Image

public void SaveImage(string imageUrl, string filename, ImageFormat format)
{    
    WebClient client = new WebClient();
    Stream stream = client.OpenRead(imageUrl);
    Bitmap bitmap;  bitmap = new Bitmap(stream);

    if (bitmap != null)
    {
        bitmap.Save(filename, format);
    }
        
    stream.Flush();
    stream.Close();
    client.Dispose();
}

Using it

try
{
    SaveImage("--- Any Image URL---", "--- Any Image Path ---", ImageFormat.Png)
}
catch(ExternalException)
{
    // Something is wrong with Format -- Maybe required Format is not 
    // applicable here
}
catch(ArgumentNullException)
{   
    // Something wrong with Stream
}

Download image from the site in .NET/C#

There is no need to involve any image classes, you can simply call WebClient.DownloadFile:

string localFilename = @"c:\localpath\tofile.jpg";
using(WebClient client = new WebClient())
{
    client.DownloadFile("http://www.example.com/image.jpg", localFilename);
}

Update
Since you will want to check whether the file exists and download the file if it does, it's better to do this within the same request. So here is a method that will do that:

private static void DownloadRemoteImageFile(string uri, string fileName)
{
    HttpWebRequest request = (HttpWebRequest)WebRequest.Create(uri);
    HttpWebResponse response = (HttpWebResponse)request.GetResponse();

    // Check that the remote file was found. The ContentType
    // check is performed since a request for a non-existent
    // image file might be redirected to a 404-page, which would
    // yield the StatusCode "OK", even though the image was not
    // found.
    if ((response.StatusCode == HttpStatusCode.OK || 
        response.StatusCode == HttpStatusCode.Moved || 
        response.StatusCode == HttpStatusCode.Redirect) &&
        response.ContentType.StartsWith("image",StringComparison.OrdinalIgnoreCase))
    {

        // if the remote file was found, download oit
        using (Stream inputStream = response.GetResponseStream())
        using (Stream outputStream = File.OpenWrite(fileName))
        {
            byte[] buffer = new byte[4096];
            int bytesRead;
            do
            {
                bytesRead = inputStream.Read(buffer, 0, buffer.Length);
                outputStream.Write(buffer, 0, bytesRead);
            } while (bytesRead != 0);
        }
    }
}

In brief, it makes a request for the file, verifies that the response code is one of OK, Moved or Redirect and also that the ContentType is an image. If those conditions are true, the file is downloaded.

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