注意 ：img 的 onload事件是异步执行的！如果你想限制图片的大小和宽高，就需要设置attachmentSimple默认不自动上传：http://docs.wex5.com/wex5-ui-question-list-2105
在 onload 事件中调用self.comp('attachmentSimple1').uploader.submit();  进行上传
Model.prototype.model1Load = function(event) {
	var data = this.comp("data1");
	var uploader = this.comp("attachmentSimple1").uploader;
	$(uploader.inputElement).attr('multiple', 'multiple');
	var _URL = window.URL || window.webkitURL;
	uploader.on('onFileSelected', function(event) {
		var file = event.file, img;
		if (file) {
			img = new Image();
			img.onload = function () {
				alert(this.width);
				alert(this.height);
				alert(file.size);
			};
			img.src = _URL.createObjectURL(file);
		}
	});
};