in this fork of South we have insert the rules for the correct migration of Photologue fields: 
in detail we added at 'South/introspection_plugins' the file 'photologue.py'
and we have modify the '__init__.py' of 'South/introspection_plugins'

With this fork is possible use of command  'manage.py schemamigration ad --initial' without error about TagField freze.