A small application for downloading website images automatically

Introduction

There is this Boston Global website called 'Big Picture' (http://www.boston.com/bigpicture/) and I love it. It shows pictures from people, animals, buildings, events, and all kinds of other stuff that is happening around the world. The quality of the images is excellent and I use them as desktop backgrounds a lot.

I found myself 'Saving as ...' a lot of images, and needed something to do this for me. The .NET framework makes it so easy to do something like this, that I wrote an application in a matter of minutes to download the images automatically.

Note: I use the pictures as background images. Please respect the photographer's rights - and don't use this app for anything illegal.

Solution

To make an application like this is really easy. What you need to do is:

Get the website contents (HTML) of a specified page
Get the image URLs from the HTML
Download all the images

So ..

What I did was add a WebBrowser component to my windows form, starting up in Google. Now the user can navigate to whatever page he/she likes. To get the source of the current document, I use the WebBrowser.Document property.
Then, we extract the IMG tags form the HTML using this method:

public static List<string> GetImagesFromWebBrowserDocument(HtmlDocument document)
{
    var result = new List<string>();
    // Get the <img> tags from the html
    foreach (HtmlElement item in document.Body.GetElementsByTagName("img"))
    {
        // Add the src attribute to the list - which contains the image url
        result.Add(item.GetAttribute("src"));
    }
    return result;
}

Finally, to download the images, I use the WebClient class:

public static void DownloadFile(string url,string destinationFolder)
{
    if (!destinationFolder.EndsWith("\\"))
        destinationFolder = string.Concat(destinationFolder, "\\");

    using (var web = new WebClient())
    {
        var source = url;
        var segments = source.Split('/');
        // Get the filename of the image - and add
        // it after the destination folder address
        var destination = destinationFolder + 
                           segments[segments.Length - 1];

        try
        {
            // Download the file
            web.DownloadFile(source, destination);
            System.Diagnostics.Debug.WriteLine(string.Format(
              "Download OK - {0} ==> {1}", source, destination));
        }
        catch
        {
            System.Diagnostics.Debug.WriteLine(string.Format(
              "Download FAILED - {0} ==> {1}", source, destination));
        }
    }
}

I added the possibility to select the download folder and added some events for updates, but that's all there is to it.

Stuff I might want to do in the future

What I could do is add a threshold for the minimum size of the image, so that logo's etc., aren't downloaded every time. Also, I don't have any checks on filenames (duplicates), but hey, it's working fine like this.