How to Change Header application/octet-stream to image/jpg while uploading a file from android

Question

I am uploading a file form sd card to server, for that i am using AndroidMultiPartEntity

but i have to change header content-type application/octet-stream to image/jpg defaultly it is taking application/octet-stream

My Code:

AndroidMultiPartEntity entity = new AndroidMultiPartEntity(new ProgressListener() {

                @Override
                public void transferred(long num) {

                    publishProgress((int) ((num / (float) totalSize) * 100));

                }
            });
File sourceFile = new File(filePath);

entity.addPart("mediaImg", new FileBody(sourceFile));
totalSize = entity.getContentLength();

            httppost.setEntity(entity);
// Making server call
            HttpResponse response = httpclient.execute(httppost);
            HttpEntity r_entity = response.getEntity();

            int statusCode = response.getStatusLine().getStatusCode();

I am using httpmime-4.3.6.jar for this

httppost.addHeader("Content-Type", "image/jpg");

i tried above one but it taking application/octet-stream

same problem https://github.com/loopj/android-async-http/issues/504