Android upload image to server using base64

I am uploading image to server using base64 its working fine if image is small but if image is big it gives me memory out exception

try {
        ByteArrayOutputStream stream = new ByteArrayOutputStream();
        bitmap.compress(Bitmap.CompressFormat.PNG, 100, stream);
        bitmap.recycle();
        byte[] byteArray = stream.toByteArray();
        stream.close();
        stream = null;
        String ba1 = Base64.encodeToString(byteArray, Base64.DEFAULT);

        bitmap = null;
        System.gc(); // immediately free bitmap

        byteArray = null;
        System.gc();
        HttpClient httpclient = new DefaultHttpClient();
        HttpPost httppost = new HttpPost(Data.upload_photo);

        JSONObject jsonObj = new JSONObject();
        jsonObj.put("user_id", LoginParser.id);
        int cnt = ba1.length() / 4;
        System.out.println("cnt=>" + cnt);
        jsonObj.put("image", ba1);

        jsonObj.put("caption", edt_caption.getText().toString());
        // Create the POST object and add the parameters

        /*
         * StringEntity entity = new StringEntity(jsonObj.toString(),
         * HTTP.UTF_8); System.out.println(entity);
         * entity.setContentType("application/json");
         * httppost.setEntity(entity);
         * 
         * HttpResponse response = httpclient.execute(httppost);
         */

        StringEntity se = new StringEntity(jsonObj.toString());
        // se.setContentEncoding(new BasicHeader(HTTP.CONTENT_TYPE,
        // "application/json"));
        se.setContentType("application/json");
        httppost.setEntity(se);
        HttpResponse response = httpclient.execute(httppost);

        String result = EntityUtils.toString(response.getEntity());
        System.out.println("=>=>" + result);
        JSONObject jsonObject = new JSONObject(result);
        if (jsonObject.getString("status").equals("success"))
            return "success";
        else
            return jsonObject.getString("message");
    } catch (IOException e) {
        e.printStackTrace();
    } catch (JSONException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    }
    return null;
}

Try this code once.

ByteArrayOutputStream bao = new ByteArrayOutputStream();
bm.compress(Bitmap.CompressFormat.JPEG, 90, bao);
byte[] ba = bao.toByteArray();
String ba1 = Base64.encodeBytes(ba);
ArrayList < NameValuePair > nameValuePairs = new
ArrayList < NameValuePair > ();
nameValuePairs.add(new BasicNameValuePair("image", ba1));
try {
    HttpClient httpclient = new DefaultHttpClient();
    HttpPost httppost = new
    HttpPost("URL STRING");
    httppost.setEntity(new UrlEncodedFormEntity(nameValuePairs));
    HttpResponse response = httpclient.execute(httppost);
    HttpEntity entity = response.getEntity();
    is = entity.getContent();
    //Toast.makeText(SignUpActivity.this, "Joining Failed", Toast.LENGTH_SHORT).show();
} catch (Exception e) {
    Log.e("log_tag", "Error in http connection " + e.toString());
}