[ticket/12500] Set a title attribute in user.img()

PHPBB3-12500
Merge pull request #2408 from prototech/ticket/12500

[ticket/12500] Set a title attribute in user.img()

* prototech/ticket/12500:
  [ticket/12500] Set a title attribute in user.img()
Merge branch 'develop-ascraeus' into develop

* develop-ascraeus:
  [ticket/12500] Set a title attribute in user.img()