diff --git a/wagtail/wagtailimages/south_migrations/0003_focal_point_fields.py b/wagtail/wagtailimages/south_migrations/0003_focal_point_fields.py
index c9b6be1f8..185d37106 100644
--- a/wagtail/wagtailimages/south_migrations/0003_focal_point_fields.py
+++ b/wagtail/wagtailimages/south_migrations/0003_focal_point_fields.py
@@ -6,6 +6,8 @@ from south.db import db
 from south.v2 import SchemaMigration
 from django.db import models
 
+from wagtail.wagtailcore.compat import AUTH_USER_MODEL, AUTH_USER_MODEL_NAME
+
 
 class Migration(SchemaMigration):
 
@@ -79,8 +81,8 @@ class Migration(SchemaMigration):
             'id': ('django.db.models.fields.AutoField', [], {'primary_key': 'True'}),
             'name': ('django.db.models.fields.CharField', [], {'max_length': '50'})
         },
-        'auth.user': {
-            'Meta': {'object_name': 'User'},
+        AUTH_USER_MODEL: {
+            'Meta': {'object_name': AUTH_USER_MODEL_NAME},
             'date_joined': ('django.db.models.fields.DateTimeField', [], {'default': 'datetime.datetime.now'}),
             'email': ('django.db.models.fields.EmailField', [], {'max_length': '75', 'blank': 'True'}),
             'first_name': ('django.db.models.fields.CharField', [], {'max_length': '30', 'blank': 'True'}),
@@ -118,7 +120,7 @@ class Migration(SchemaMigration):
             'height': ('django.db.models.fields.IntegerField', [], {}),
             'id': ('django.db.models.fields.AutoField', [], {'primary_key': 'True'}),
             'title': ('django.db.models.fields.CharField', [], {'max_length': '255'}),
-            'uploaded_by_user': ('django.db.models.fields.related.ForeignKey', [], {'to': "orm['auth.User']", 'null': 'True', 'blank': 'True'}),
+            'uploaded_by_user': ('django.db.models.fields.related.ForeignKey', [], {'to': "orm['%s']" % AUTH_USER_MODEL, 'null': 'True', 'blank': 'True'}),
             'width': ('django.db.models.fields.IntegerField', [], {})
         },
         'wagtailimages.rendition': {
@@ -133,4 +135,4 @@ class Migration(SchemaMigration):
         }
     }
 
-    complete_apps = ['wagtailimages']
\ No newline at end of file
+    complete_apps = ['wagtailimages']
diff --git a/wagtail/wagtailimages/south_migrations/0004_auto__chg_field_rendition_focal_point_key.py b/wagtail/wagtailimages/south_migrations/0004_auto__chg_field_rendition_focal_point_key.py
index f22008623..e1c17d342 100644
--- a/wagtail/wagtailimages/south_migrations/0004_auto__chg_field_rendition_focal_point_key.py
+++ b/wagtail/wagtailimages/south_migrations/0004_auto__chg_field_rendition_focal_point_key.py
@@ -6,6 +6,8 @@ from south.db import db
 from south.v2 import SchemaMigration
 from django.db import models
 
+from wagtail.wagtailcore.compat import AUTH_USER_MODEL, AUTH_USER_MODEL_NAME
+
 
 class Migration(SchemaMigration):
 
@@ -39,8 +41,8 @@ class Migration(SchemaMigration):
             'id': ('django.db.models.fields.AutoField', [], {'primary_key': 'True'}),
             'name': ('django.db.models.fields.CharField', [], {'max_length': '50'})
         },
-        'auth.user': {
-            'Meta': {'object_name': 'User'},
+        AUTH_USER_MODEL: {
+            'Meta': {'object_name': AUTH_USER_MODEL_NAME},
             'date_joined': ('django.db.models.fields.DateTimeField', [], {'default': 'datetime.datetime.now'}),
             'email': ('django.db.models.fields.EmailField', [], {'max_length': '75', 'blank': 'True'}),
             'first_name': ('django.db.models.fields.CharField', [], {'max_length': '30', 'blank': 'True'}),
@@ -78,7 +80,7 @@ class Migration(SchemaMigration):
             'height': ('django.db.models.fields.IntegerField', [], {}),
             'id': ('django.db.models.fields.AutoField', [], {'primary_key': 'True'}),
             'title': ('django.db.models.fields.CharField', [], {'max_length': '255'}),
-            'uploaded_by_user': ('django.db.models.fields.related.ForeignKey', [], {'to': "orm['auth.User']", 'null': 'True', 'blank': 'True'}),
+            'uploaded_by_user': ('django.db.models.fields.related.ForeignKey', [], {'to': "orm['%s']" % AUTH_USER_MODEL, 'null': 'True', 'blank': 'True'}),
             'width': ('django.db.models.fields.IntegerField', [], {})
         },
         'wagtailimages.rendition': {
@@ -93,4 +95,4 @@ class Migration(SchemaMigration):
         }
     }
 
-    complete_apps = ['wagtailimages']
\ No newline at end of file
+    complete_apps = ['wagtailimages']