ASP.net image resizing

<%@ Page Trace="False" Language="vb" aspcompat="false" debug="true" validateRequest="false"%>
<%@ Import Namespace=System.Drawing %>
<%@ Import Namespace=System.Drawing.Imaging %>
<%@ Import Namespace=System %>
<%@ Import Namespace=System.Web %>
<SCRIPT LANGUAGE="VBScript" runat="server">
    Const Lx = 173 ' max width for thumbnails
    Const Ly = 234 ' max height for thumbnails
    Const upload_dir = "images/" ' directory to upload file
    Const upload_original = "big" ' filename to save original as (suffix added by script)
    Const upload_thumb = "small" ' filename to save thumbnail as (suffix added by script)
    Const upload_max_size = 5000 ' max size of the upload (KB) note: this doesn't override any server upload limits
    Dim fileExt ' used to store the file extension (saves finding it mulitple times)
    Dim newWidth, newHeight As Integer ' new width/height for the thumbnail
    Dim l2 ' temp variable used when calculating new size
    Dim fileFld As HttpPostedFile ' used to grab the file upload from the form
    Dim originalimg As System.Drawing.Image ' used to hold the original image
    Dim msg ' display results
    Dim upload_ok As Boolean ' did the upload work ?
</script>


<%
    Randomize() ' used to help the cache-busting on the preview images
    upload_ok = False
    If LCase(Request.ServerVariables("REQUEST_METHOD")) = "post" Then
        fileFld = Request.Files(0) ' get the first file uploaded from the form (note:- you can use this to itterate through more than one image)
        If fileFld.ContentLength > upload_max_size * 1024 Then
            msg = "Sorry, the image must be less than " & upload_max_size & "Kb"
        Else
            Try
                originalimg = System.Drawing.Image.FromStream(fileFld.InputStream)
                ' work out the width/height for the thumbnail. Preserve aspect ratio and honour max width/height
                ' Note: if the original is smaller than the thumbnail size it will be scaled up
                If (originalimg.Width / Lx) > (originalimg.Width / Ly) Then
                    l2 = originalimg.Width
                    newWidth = Lx
                    newHeight = originalimg.Height * (Lx / l2)
                    If newHeight > Ly Then
                        newWidth = newWidth * (Ly / newHeight)
                        newHeight = Ly
                    End If
                Else
                    l2 = originalimg.Height
                    newHeight = Ly
                    newWidth = originalimg.Width * (Ly / l2)
                    If newWidth > Lx Then
                        newHeight = newHeight * (Lx / newWidth)
                        newWidth = Lx
                    End If
                End If
                Dim thumb As New Bitmap(newWidth, newHeight)
                'Create a graphics object
                Dim gr_dest As Graphics = Graphics.FromImage(thumb)
                ' just in case it's a transparent GIF force the bg to white
                Dim sb = New SolidBrush(System.Drawing.Color.White)
                gr_dest.FillRectangle(sb, 0, 0, thumb.Width, thumb.Height)
                'Re-draw the image to the specified height and width
                gr_dest.DrawImage(originalimg, 0, 0, thumb.Width, thumb.Height)
                Try
                    fileExt = System.IO.Path.GetExtension(fileFld.FileName).ToLower()
                    originalimg.Save(Server.MapPath(upload_dir & TextBoxFileName.Text.ToString & "-" & upload_original & fileExt), originalimg.RawFormat)
                    thumb.Save(Server.MapPath(upload_dir & TextBoxFileName.Text.ToString & "-" & upload_thumb & fileExt), originalimg.RawFormat)
                    msg = "Uploaded " & fileFld.FileName & " to " & Server.MapPath(upload_dir & upload_original & fileExt)
                    upload_ok = True
                Catch ex As Exception
                    msg = "Sorry, there was a problem saving the image."
                End Try
                ' Housekeeping for the generated thumbnail
                If Not thumb Is Nothing Then
                    thumb.Dispose()
                    thumb = Nothing
                End If
            Catch
                msg = "Sorry, that was not an image we could process."
            End Try
        End If
        ' House Keeping !
        If Not originalimg Is Nothing Then
            originalimg.Dispose()
            originalimg = Nothing
        End If
    End If
%>
<html>
<head>
<title>ASP.NET File Upload and Resize Sample</title>
<META NAME="Description" CONTENT="ASP.NET File Upload and Resize Sample (Hybrid VB.NET)">
<META NAME="Keywords" CONTENT="ASP.NET, ASP, NET, VB, VBScript, Image, Upload, Resize, Thumbnail, Constrain, Filesize, File, Size, Free">
<META NAME="Copyright" CONTENT="Rufan-Redi Pty Ltd 2005">
<META NAME="Author" CONTENT="System developed by Jeremy at http://www.Rufan-Redi.com">
</head>
<body>

<p><b>Hybrid ASP.NET File Upload and Resize Sample (VB.NET)</b>
<br>Upload and resize a GIP/JPG/PNG images, ensuring filesizes are optimum.</p>

<form id="Form1" enctype="multipart/form-data" method="post" runat="server">
<table>
<tr><td>Select the file to upload:</td><td><input type="file" name="upload_file"></td></tr>
    <tr>
        <td colspan="2" style="height: 19px">
            New FileName:
            <asp:TextBox ID="TextBoxFileName" runat="server"></asp:TextBox></td>
    </tr>
<tr><td colspan=2>Max upload size <%=upload_max_size%>Kb, gif/jpg/png only. The image will be saved as&nbsp; "New FileName-small" and
    "New FileName-big" accordingly. Just make sure that the original image is 260px
    x 351px big</td></tr>
<tr><td colspan=2><input type="submit" value="Upload" id="Submit1" language="javascript" onclick="return Submit1_onclick()">
</table>
</form>

<%
    If upload_ok Then
%>
<table>
<tr>
<td valign=top><img src="<%=upload_dir & TextBoxFileName.Text.ToString & "-" & upload_original & fileExt & "?" & rnd()%>"></td>
<td valign=top><img src="<%=upload_dir & TextBoxFileName.Text.ToString & "-" & upload_thumb & fileExt & "?" & rnd()%>"></td>
</tr>
</table>
<%
Else
    Response.Write(msg)
End If
%>
</body>
</html>

//Loop through each uploaded file
foreach (string fileKey in HttpContext.Current.Request.Files.Keys) {
  HttpPostedFile file = HttpContext.Current.Request.Files[fileKey];

  //Get the physical path for the uploads folder
  string uploadFolder = MapPath("~/uploads");

  //Create the upload folder if it is missing
  if (!Directory.Exists(uploadFolder)) Directory.CreateDirectory(uploadFolder);

  //The resizing settings can specify any of 30 commands.. See imageresizing .net for details.
  ResizeSettings resizeCropSettings = new ResizeSettings("maxwidth=1024&maxheight=768&format=jpg");

  //Generate a filename (GUIDs are safest).
  string fileName = Path.Combine(uploadFolder, System.Guid.NewGuid().ToString());

  //What final type of file will we have? This can depend on whether the resizeCropSettings sepcifies a format,
  // and what the original format was (if resizecropSettings doesn't specify one)
  fileName += "." + ImageBuilder.Current.EncoderProvider.GetEncoder(resizeCropSettings, fileUpload.PostedFile.FileName).Extension;

  //Resize the image
  ImageBuilder.Current.Build(file, fileName, resizeCropSettings);
}