This is a great use case. My sister-in-law gave her mom her Facebook account login so she can see pictures of the grandkids without having to sign up for a Facebook account.
couldn't you just email them the photos and bypass another process altogether? We're just coming full circle. email photos to friends, facebook post, now back to email photos to friends because facebook's not adding any value.
Email is the endgame. Right now, the natural flow for millions is to post photos to Instagram or Facebook. PicDigest fits that flow without any other steps.
The next major iteration of PicDigest will bypass both posting to social networks AND the step of sending photos by email. It'll change the world!!! [insert evil laugh]