title: Byte file conversion via python 3
body: <p>Is there any simple way for me to read the contents of a binary file as a binary string, turn it into a normal (utf-8) string, do some operations with it, turn it back into a binary string and write it into a binary file? I tried doing something as simple as:</p>
  
  <pre><code>a_file = open('image1.png', 'rb')
  text = b''
  for a_line in a_file:
      text += a_line
  a_file.close()
  text2 = text.decode('utf-8')
  text3 = text2.encode()
  a_file = open('image2.png', 'wb')
  a_file.write(text3)
  a_file.close()
  </code></pre>
  
  <p>but I get 'Unicode can not decode bytes in position...'</p>
  
  <p>What am I doing terribly wrong?</p>