Try below code…
Intent emailIntent = new Intent(android.content.Intent.ACTION_SEND);
emailIntent.setType("application/image");
emailIntent.putExtra(android.content.Intent.EXTRA_EMAIL, new String[]{strEmail});
emailIntent.putExtra(android.content.Intent.EXTRA_SUBJECT,"Test Subject");
emailIntent.putExtra(android.content.Intent.EXTRA_TEXT, "From My App");
emailIntent.putExtra(Intent.EXTRA_STREAM, Uri.parse("file:///mnt/sdcard/Myimage.jpeg"));
startActivity(Intent.createChooser(emailIntent, "Send mail..."));