get image link javascript

[Object, "data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAABn8A…AAAECBAgQIECAAAECpQT+BfU1qcHgIH6iAAAAAElFTkSuQmCC"]

FB.ui(
 {
 method: 'feed',
 name: 'DebugmodeEventPlans',
 link: 'http:localhost:1461/ShareonFB.html',
 picture:need to pass it here,
 caption: 'hey how is my Application ? tell me dude',
 description: 'hey how is my Application ?',
 message: ''
 });