Resize image while uploading - asp.net

Question

i am using file upload control for uploading images.
in that iam checking the condition,if Image.Width > 250 || Image.Height > 400 then i am resizing the image.
but it is giving the error
"The SaveAs method is configured to require a rooted path, and the path 'ProductImages/roman_sandals.jpg' is not rooted."
ProductImages is folder where i am saving image.
Can anyone find why this is giving error,my code is
string strBigServerPath = AppHardcodeValue.productImgPath;
string strFileName = "";
if (prodImg.HasFile)
{
strFileName = prodImg.PostedFile.FileName;
string uniqueNum = Convert.ToString(System.Guid.NewGuid());
string shortFileName = System.IO.Path.GetFileName(strFileName);
string Extension = System.IO.Path.GetExtension(prodImg.FileName);
string newFileName = shortFileName;
prodImg.SaveAs(Server.MapPath(strBigServerPath + newFileName));
using (System.Drawing.Image Img =
System.Drawing.Image.FromFile(Server.MapPath(strBigServerPath) + newFileName))
{
if (Img.Width > 250 || Img.Height > 400)
{
Size MainSize = new Size(250, 400);
using (System.Drawing.Image ImgThnail =
new Bitmap(Img, MainSize.Width, MainSize.Height))
{
prodImg.SaveAs(strBigServerPath + newFileName);
}
}
Img.Dispose();
}
string ThumbnailPath = Server.MapPath(AppHardcodeValue.productThumbImgPath) + newFileName;
using (System.Drawing.Image Img =
System.Drawing.Image.FromFile(Server.MapPath(strBigServerPath) + newFileName))
{
Size ThumbNailSize = new Size(50, 50);
using (System.Drawing.Image ImgThnail =
new Bitmap(Img, ThumbNailSize.Width, ThumbNailSize.Height))
{
ImgThnail.Save(ThumbnailPath, Img.RawFormat);
ImgThnail.Dispose();
}
Img.Dispose();
}
}

Answer 1

You can use
HostingEnvironment.ApplicationPhysicalPath
in this case, and combine it with your image path.
For example:
Path.Combine(HostingEnvironment.ApplicationPhysicalPath, "ProductImages/roman_sandals.jpg");
which will give you a rooted path. The folder "ProductImages" has to be located in the applications directory.
See here for details: http://msdn.microsoft.com/en-us/library/system.web.hosting.hostingenvironment.applicationphysicalpath.aspx