if (fu.HasFile)
{
Trace.Write("We found a image to upload");
HttpPostedFile userPostedFile = fu.PostedFile;
ImageUploader imageUploader = new ImageUploader("C:/sökväg/på/server/", userPostedFile, "Namnpåbild.jpg");
//Utlämna mått för att behålla orginalstorlek på bilden
imageUploader.IntMaxWidth = 150;
imageUploader.IntMaxHeight = 50;
bool boolStatus = imageUploader.UploadImage();
if(boolStatus)
Trace.Write("Image uploaded!");
}

using System;
using System.Data;
using System.Data.SqlClient;
using System.Configuration;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Web.UI.HtmlControls;
using System.Drawing;
using System.Drawing.Imaging;


/// <summary>
/// Summary description for ImageUploader
/// </summary>
public class ImageUploader : Page
{

//Lokala variabler
private HttpPostedFile userPostedFile = null;
private string strWhereStatement = null;
private string strRootPath = string.Empty;
private string strImageName = string.Empty;
private int intMaxWidth;
private int intMaxHeight;

//Properties
public string StrRootPath
{
get { return strRootPath; }
set { strRootPath = value; }
}
public string StrImageName
{
get { return strImageName; }
set { strImageName = value; }
}
public int IntMaxWidth
{
get { return intMaxWidth; }
set { intMaxWidth = value; }
}
public int IntMaxHeight
{
get { return intMaxHeight; }
set { intMaxHeight = value; }
}


//I första konstruktorn använder vi filens orginalnamn
public ImageUploader(string StrRootPath,HttpPostedFile UserPostedFile)
{
strRootPath = StrRootPath;
userPostedFile = UserPostedFile;
//Ta bort eventuell filändelse
strImageName = userPostedFile.FileName.Remove(userPostedFile.FileName.LastIndexOf("."));
//UploadImage(userPostedFile);
}
//I den utökade så skickar vi med ett eget filnamn
public ImageUploader(string StrRootPath,HttpPostedFile UserPostedFile,string StrImageName)
{
strRootPath = StrRootPath;
userPostedFile = UserPostedFile;

strImageName = StrImageName;
}



public bool UploadImage()
{
bool tooHigh = false;
bool tooWide = false;
bool doUpload = false;
bool uploaded = false;
string strFileExt = string.Empty;

try
{

//Kontrollera att filen är större än 0KB
if (userPostedFile.ContentLength > 0)
{

//Check på filändelse och om man ska tillåta uppladdning

//Jpg och Jpeg
if (userPostedFile.ContentType.Equals("image/jpeg") || userPostedFile.ContentType.Equals("image/pjpeg"))
{
doUpload = true;
strImageName += ".jpg";
}
//Gif
if (userPostedFile.ContentType.Equals("image/gif"))
{
doUpload = true;
strImageName += ".gif";
}
//Bmp
if (userPostedFile.ContentType.Equals("image/bmp"))
{
doUpload = true;
strImageName += ".bmp";
}
//Png
if (userPostedFile.ContentType.Equals("image/png"))
{
doUpload = true;
strImageName += ".png";
}

System.Drawing.Bitmap bitmap = new System.Drawing.Bitmap(userPostedFile.InputStream, false);

//Kolla höjd
if (intMaxHeight != null)
{
if (bitmap.Height > intMaxHeight)
{
doUpload = true;
tooHigh = true;
}
}

//Kolla bredd
if (intMaxWidth != null)
{
if (bitmap.Width > intMaxWidth)
{
doUpload = true;
tooWide = true;
}
}

Trace.Write(strRootPath + strImageName);
if (doUpload && bitmap != null)
{
Trace.Write("doUpload!!");

//Förminska om den är för stor, och ladda upp
if (tooHigh || tooWide)
{
Trace.Write("tooBig!!");
//Skapa liten automagiskt
double photoWidth, photoHeight;
double percentageDifference = 0;

photoWidth = intMaxWidth;


//Nya mått på bilden.
percentageDifference = bitmap.Width / photoWidth;
photoHeight = bitmap.Height / percentageDifference;

//Kolla även höjden
if (photoHeight > intMaxHeight)
{
photoHeight = intMaxHeight;
percentageDifference = bitmap.Height / photoHeight;
photoWidth = bitmap.Height / percentageDifference;
}

Bitmap outputBitMap = CreateThumbnail(bitmap, Convert.ToInt32(photoWidth), Convert.ToInt32(photoHeight));

//Kolla vad det är för format
ImageFormat imageFormat = outputBitMap.RawFormat;

//Spara bilden
outputBitMap.Save(@"" + strRootPath + strImageName, imageFormat);
uploaded = true;
}
//Ladda upp orginalbilden om den är inom måtten
else
{
Trace.Write("Rätt storlek eller mindre.");


userPostedFile.SaveAs(@"" + strRootPath + strImageName);
uploaded = true;
}

}

}
}
catch(Exception objException)
{
Trace.Write("Upload fel!", objException.Message);
uploaded=false;
}
return uploaded;
}

//Tar emot en BitMap och gör den mindre
public static Bitmap CreateThumbnail(Bitmap loBMP, int lnWidth, int lnHeight)
{
System.Drawing.Bitmap bmpOut = null;

try
{

ImageFormat loFormat = loBMP.RawFormat;
decimal lnRatio;
int lnNewWidth = 0;
int lnNewHeight = 0;

//Om bilden är större än en thumbnail, returnera den.
if (loBMP.Width < lnWidth && loBMP.Height < lnHeight)
return loBMP;

if (loBMP.Width > loBMP.Height)
{
lnRatio = (decimal)lnWidth / loBMP.Width;
lnNewWidth = lnWidth;
decimal lnTemp = loBMP.Height * lnRatio;
lnNewHeight = (int)lnTemp;
}
else
{
lnRatio = (decimal)lnHeight / loBMP.Height;
lnNewHeight = lnHeight;
decimal lnTemp = loBMP.Width * lnRatio;
lnNewWidth = (int)lnTemp;
}

bmpOut = new Bitmap(lnNewWidth, lnNewHeight);
Graphics g = Graphics.FromImage(bmpOut);
g.InterpolationMode = System.Drawing.Drawing2D.InterpolationMode.HighQualityBicubic;
g.FillRectangle(Brushes.White, 0, 0, lnNewWidth, lnNewHeight);
g.DrawImage(loBMP, 0, 0, lnNewWidth, lnNewHeight);
loBMP.Dispose();
}
catch
{
return null;
}
return bmpOut;
}
}

<asp:Label id="lblMessage" runat="server">
<br />
<br />
<asp:FileUpLoad id="fuImage" runat="server" />

<asp:RegularExpressionValidator
id="fuValidator" runat="server"
ErrorMessage="Upload Jpegs and Gifs only."
ValidationExpression="^(([a-zA-Z]:)|(\\{2}\w+)\$?)(\\(\w[\w].*))(.jpg|.JPG|.gif|.GIF)$"
ControlToValidate="fuImage">
</asp:RegularExpressionValidator>

<asp:Button id="buttonUpload" Text="Upload File" OnClick="buttonUpload_Click" runat="server" Width="105px" />

protected void buttonUpload_Click(object sender, EventArgs e)
{
if (fuImage.HasFile)
{

fuImage.SaveAs(@"C:\temp\" + fuImage.FileName);
lblMessage.Text = "Fil laddades upp: " + fuImage.FileName ;
}
else
{
lblMessage.Text = "Det fanns ingen fil i formuläret!";
}
}

<httpRuntime maxRequestLength = "4096" />