saving pdf file as a Image

Hi all
i want to convert pdf file to image.
am using the following code for reading pdf file to bytes


FileStream fs=new FileStream("C:\test.pdf",FileMode.Open,FileAccess.Read);
byte[] bytes=new bytes[fs.Length];
fs.Read(bytes,0,system.convert.ToInt32(fs.Length));
fs.close();


writing that bytes to image
FileStream fs1=new FileStream("C:\test.JPG",FileMode.Create,FileAccess.Write);
fs1.Write(bytes,0,bytes.Length);
fs1.close()
i am able to create the Image ,but when i open it saying "no preview available"
please can u suggest me in right way....







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