How do I read a raw byte array from any file, and write that byte array back into a new file?
(edit: note that the question changed; it didn't mention byte[] initially; see revision 1)
Well, File.Copy leaps to mind; but otherwise this sounds like a Stream scenario:
using (Stream source = File.OpenRead(inPath))
using (Stream dest = File.Create(outPath)) {
byte[] buffer = new byte[2048]; // pick size
int bytesRead;
while((bytesRead = source.Read(buffer, 0, buffer.Length)) > 0) {
dest.Write(buffer, 0, bytesRead);
}
}