Currently Whatsapp supports Image and Text sharing at the same time. (Nov 2014).
Here is an example of how to do this:
/**
* Show share dialog BOTH image and text
*/
Uri imageUri = Uri.parse(pictureFile.getAbsolutePath());
Intent shareIntent = new Intent();
shareIntent.setAction(Intent.ACTION_SEND);
//Target whatsapp:
shareIntent.setPackage("com.whatsapp");
//Add text and then Image URI
shareIntent.putExtra(Intent.EXTRA_TEXT, picture_text);
shareIntent.putExtra(Intent.EXTRA_STREAM, imageUri);
shareIntent.setType("image/jpeg");
shareIntent.addFlags(Intent.FLAG_GRANT_READ_URI_PERMISSION);
try {
startActivity(shareIntent);
} catch (android.content.ActivityNotFoundException ex) {
ToastHelper.MakeShortText("Whatsapp have not been installed.");
}