For the way I use whatsapp (informal/stupid chat) I usually don't need to send full resolution photos (also to save bandwidth when on 3g). If I really need to send a full resolution image, I use email.
I noticed that the images my friends send me are less than 50kb on average, I sent only one taken with the Jolla and it was 1,3mb (and crashed my friend's iPhone's whatsapp, poor silly thing ).