gistfile1.js

function makeD3Post(post_url, avatar_url, note_count){
  var D3Post = {
		post: post_url,
		avatar: avatar_url,
		notes: note_count,
		dimensions: {
			'post': {
				'width': 0,
				'height': 0
			},
 
			'avatar': {
				'width': 0,
				'height': 0
			}
		}
    };

    D3Post.prototype.preload = function(){
			var loader = new PxLoader(),
				post_image = new PxLoaderImage(D3Post.post),
				avatar_image = new PxLoaderImage(D3Post.avatar),
				dimensions = D3Post.dimensions;
 
			loader.add(post_image);
			loader.add(avatar_image);
 
			loader.addCompletionListener(function() {
				D3Post.dimensions.post.width = post_image.img.width;
				D3Post.dimensions.post.height = post_image.img.height;
				D3Post.dimensions.avatar.width = avatar_image.img.width;
				D3Post.dimensions.avatar.height = avatar_image.img.height;
			});
 
			loader.start();
		},
 
	D3Post.prototype.test = function(){
			console.log(D3Post.dimensions);
			var d = D3Post.dimensions;
			console.log(d['avatar']);
		}
	};
 
	return D3Post;
}

var post_1 = makeD3Post(post_url, avatar_url, note_count);
post_1.preload();
console.log(post_1);
post_1.test();