def METHOD_NAME(apps, schema_editor):
    # This operation assumes CustomImage instances will be created with their
    # original Image instance primary keys reserved.
    Image = apps.get_model('wagtailimages.Image')
    CustomImage = apps.get_model('common.CustomImage')
    for original_image in Image.objects.all():
        values = dict()
        for field in original_image._meta.fields:
            values[field.name] = getattr(original_image, field.name)
        CustomImage.objects.create(**values)