Download image from the site in .NET/C#

Question

I am trying to download images from the site. The code which I am using is working fine while the image is available. If the image it not available it is creating a problem. How to validate availability of the image?

Code:

Method 1:

WebRequest requestPic = WebRequest.Create(imageUrl);

WebResponse responsePic = requestPic.GetResponse();

Image webImage = Image.FromStream(responsePic.GetResponseStream()); // Error

webImage.Save("D:\\Images\\Book\\" + fileName + ".jpg");

Method 2:

WebClient client = new WebClient();
Stream stream = client.OpenRead(imageUrl);

bitmap = new Bitmap(stream); // Error : Parameter is not valid.
stream.Flush();
stream.Close();
client.dispose();

if (bitmap != null)
{
    bitmap.Save("D:\\Images\\" + fileName + ".jpg");
}

Edit:

Stream has the following statements:

      Length  '((System.Net.ConnectStream)(str)).Length' threw an exception of type  'System.NotSupportedException'    long {System.NotSupportedException}
    Position  '((System.Net.ConnectStream)(str)).Position' threw an exception of type 'System.NotSupportedException'    long {System.NotSupportedException}
 ReadTimeout  300000    int
WriteTimeout  300000    int

Wrap the offending statement with `try - catch`, and provide us with exception details. — gimel, Sep 01 '10 at 07:25
the line bitmap = new Bitmap(stream); shows error: Parameter is not valid. — Geeth, Sep 01 '10 at 09:26

Fredrik Mörk · Accepted Answer · 2010-09-01T10:19:56.703

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.

@Geetha: do you get an image if you try to navigate to the given URL in a web browser? — Fredrik Mörk, Sep 01 '10 at 08:08
@Geetha: it sounds as if you would first want to check if the image exists, then download it. For that first step, check here: http://stackoverflow.com/questions/1379371/c-is-there-a-faster-way-to-check-if-an-external-web-page-exists — Fredrik Mörk, Sep 01 '10 at 08:40
It is taking too much of time and also downloading blank image. the line bitmap = new Bitmap(stream); shows error: Parameter is not valid — Geeth, Sep 01 '10 at 09:41
"There is no need to involve any image classes". Actually there is a need if you're intention is download an image, manipulate it and simply display it. There is no need to store a file or even fill up a disk with images if there is no need to store the file. — Johann, Nov 27 '13 at 08:06

score 26 · Answer 2 · answered Sep 27 '12 at 22:44

I have used Fredrik's code above in a project with some slight modifications, thought I'd share:

private static bool DownloadRemoteImageFile(string uri, string fileName)
{
    HttpWebRequest request = (HttpWebRequest)WebRequest.Create(uri);
    HttpWebResponse response;
    try
    {
        response = (HttpWebResponse)request.GetResponse();
    }
    catch (Exception)
    {
        return false;
    }

    // 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 it
        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);
        }
        return true;
    }
    else
        return false;
}

Main changes are:

using a try/catch for the GetResponse() as I was running into an exception when the remote file returned 404
returning a boolean

thank you - looks like well written code and works well in my application — bernhardrusch, May 03 '13 at 08:42
Why return a boolean flag when you can throw an exception? It's always better until you have performance problems. SRP does not allow to have these methods. — Alex Zhukovskiy, Sep 16 '15 at 04:58

score 5 · Answer 3 · answered Apr 12 '17 at 15:10

Also possible to use DownloadData method

    private byte[] GetImage(string iconPath)
    {
        using (WebClient client = new WebClient())
        {
            byte[] pic = client.DownloadData(iconPath);
            //string checkPath = Environment.GetFolderPath(Environment.SpecialFolder.MyDocuments) +@"\1.png";
            //File.WriteAllBytes(checkPath, pic);
            return pic;
        }
    }

score 0 · Answer 4 · answered Dec 05 '16 at 16:10

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

            if ((response.StatusCode == HttpStatusCode.OK ||
                response.StatusCode == HttpStatusCode.Moved ||
                response.StatusCode == HttpStatusCode.Redirect) &&
                response.ContentType.StartsWith("image", StringComparison.OrdinalIgnoreCase)) 
            {
                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);
                }
            }
        }

Perhaps you could explain this code, and _why_ it works? – Nissa Dec 05 '16 at 16:32 — Nissa, Dec 05 '16 at 16:32

score 0 · Answer 5 · answered Feb 16 '19 at 13:15

0

The best practice to download an image from Server or from Website and store it locally.

WebClient client=new Webclient();
client.DownloadFile("WebSite URL","C:\\....image.jpg");
client.Dispose();

answered Feb 16 '19 at 13:15

Mohamad-Al-Ibrahim

13
1
8

score 0 · Answer 6 · answered Mar 01 '20 at 13:16

You can use this code

using (WebClient client = new WebClient()) {
                    Stream stream = client.OpenRead(imgUrl);
                    if (stream != null) {
                        Bitmap bitmap = new Bitmap(stream);
                        ImageFormat imageFormat = ImageFormat.Jpeg;
                        if (bitmap.RawFormat.Equals(ImageFormat.Png)) {
                            imageFormat = ImageFormat.Png;
                        }
                        else if (bitmap.RawFormat.Equals(ImageFormat.Bmp)) {
                            imageFormat = ImageFormat.Bmp;
                        }
                        else if (bitmap.RawFormat.Equals(ImageFormat.Gif)) {
                            imageFormat = ImageFormat.Gif;
                        }
                        else if (bitmap.RawFormat.Equals(ImageFormat.Tiff)) {
                            imageFormat = ImageFormat.Tiff;
                        }

                        bitmap.Save(fileName, imageFormat);
                        stream.Flush();
                        stream.Close();
                        client.Dispose();
                    }
                }

Project available at: github

Download image from the site in .NET/C#

6 Answers6

Linked

Related