You should not create an Image
from the stream (it will only store the first frame). Instead, you should write the contents of the Stream
directly to disk using, for example, the Stream.CopyTo
method to copy the content to a FileStream
you created for the destination file.
using (Stream stream = httpWebReponse.GetResponseStream())
using (FileStream fs = File.Create(path))
{
stream.CopyTo(fs);
}