What's the data structure that needed by services for posting new node with drupal7 services? I have content type named "shen" and gona to create new node with services module from crawl machine data.

For now, it can login in system and post new node but it can't save image field data.

this is the data It post to services module:

{'body': {'und': {'0': {'value': 'I am Shen'}}}, 'type': 'shen', 'field_shen_image': {'und': {'0': {'new': 1, 'display': 1, 'fid': '541'}}}, 'title': 'just a little title'}


I'm sure lost a little thing and really need your help.

Cheers
Corrected JSON format and tested on my local environment. 



{
    "body": {
        "und": [
            {
                "value": "IamShen"
            }
        ]
    },
    "type": "shen",
    "field_shen_image": {
        "und": [
            {
                "new": 1,
                "display": 1,
                "fid": 541
            }
        ]
    },
    "title": "justalittletitle"
}