Resizing and processing images as they are uploaded is very straightforward. Most of the required code is about paths and directories.

The following sample code generates a GUID filename for each upload, determines the appropriate file extension that is needed, then resizes/crops/formats the image according to the specified ResizeSettings.

//Loop through each uploaded file
foreach (string fileKey in HttpContext.Current.Request.Files.Keys) 
{
    HttpPostedFile file = HttpContext.Current.Request.Files[fileKey];
    if (file.ContentLength <= 0) continue; //Skip unused file controls.

    //The resizing settings can specify any of 30 commands.. See http://imageresizing.net for details.
    //Destination paths can have variables like <guid> and <ext>, or 
    //even a santizied version of the original filename, like <filename:A-Za-z0-9>
    ImageResizer.ImageJob i = new ImageResizer.ImageJob(file, "~/uploads/<guid>.<ext>", new ImageResizer.ResizeSettings( 
                            "width=2000;height=2000;format=jpg;mode=max"));
    i.CreateParentDirectory = true; //Auto-create the uploads directory.
    i.Build();
}

For VB.NET users

'Loop through each uploaded file
For Each fileKey As String In HttpContext.Current.Request.Files.Keys
        Dim file As HttpPostedFile = HttpContext.Current.Request.Files(fileKey)
        If (file.ContentLength > 0) Then 'Skip unused file controls.
            'The resizing settings can specify any of 30 commands.. See http://imageresizing.net for details.
            'Destination paths can have variables like <guid> and <ext>, or 
            'even a santizied version of the original filename, like <filename:A-Za-z0-9>
            Dim i As ImageResizer.ImageJob = New ImageResizer.ImageJob(file, "~/uploads/<guid>.<ext>", New ImageResizer.ResizeSettings("width=2000;height=2000;format=jpg;mode=max"))
            i.CreateParentDirectory = True 'Auto-create the uploads directory.
            i.Build()
        End If
Next