If a user uploads a new revision of an image in Pholio, it is only visibile to him.
Other users see only "missing.png"

phabricator f2fcafb40dde94ddf4ee22716fea74fca0334a64 (Wed, May 31) 
arcanist 129d51fa0936c9bae48fadf3a3f39e26d69d24da (Thu, May 18) 
phutil a900d7b63e954e221efe140f0f33d3d701524aae (Apr 23 2017)

Steps to reproduce:

• USER 1:
  1. create a new pholio mock
  2. upload image
  3. save
• USER 2:
  1. Open Pholio mock, verify image is visible
• USER 1(or 2):
  1. Upload new revision of image (same pholio mock)
  2. See two images (Ref Image 1)
• USER 2 (or1):
  1. reload pholio mock, see only first uploaded image, not latest revision (Ref. Image 2)

User 1	User 2