Recently I worked on integration between Drupal CMS with backend SOAP service and encountered a problem with saving image to the backend. The backend required image to be passed as byte array. Googling around I was suprised to find out answers like "I don't think PHP has such low level control..." or "change your backend service...". Eventually after not finding anything useful I decided to tackle the issue myself and soon I came up with a solution which is actually very easy.