MergeMappingException

[cocoakeith]

when I try

curl -XPUT 'localhost:9200/test/test/_mapping' -d '{
    "test": {
        "properties": {
            "my_img": {
                "type": "image",
                "feature": {
                    "CEDD": {
                        "hash": "BIT_SAMPLING"
                    },
                    "JCD": {
                        "hash": ["BIT_SAMPLING", "LSH"]
                    },
                    "FCTH": {}
                },
                "metadata": {
                    "jpeg.image_width": {
                        "type": "string",
                        "store": "yes"
                    },
                    "jpeg.image_height": {
                        "type": "string",
                        "store": "yes"
                    }
                }
            }
        }
    }
}' 

with elasticsearch1.0.1 and elasticsearch-image1.2.0, it return {"error":"MergeMappingException[Merge failed with failures {[mapper [my_img] of different type, current_type [string], merged_type [ImageMapper]]}]","status":400}, how should I to solve it?