使用ajax上传图像会在JSON数据之后提供非空白字符？

I am getting this error while uploading image using ajax,

SyntaxError: JSON.parse: unexpected non-whitespace character after JSON data

I googled, but not found any appropriate answer,

Here is my ajax function,

$(document).ready(function(){
    $('#image').on('change', function(){
        $("#frm_name").ajaxForm({
            success: function(data) {
                res = $.parseJSON(data);
                if(res.status === 1){
                    alert('success');
                    var html = "<img src='<?=base_url();?>' + 'public/images/' + '"+res.image_name+"' class='preview' width='100' height='100' />";
                        $("#preview").html(html);
                        $("#frm_name").ajaxFormUnbind();
                }
                if(res.status === 0){
                    $("#frm_name").ajaxFormUnbind();
                }
            }
        }).submit();
    });
});

On the other side, i am encoding as,

echo json_encode(array('status'=>1, 'image_name'=>$this->upload->file_name));

and response is,

{"status":1,"image_name":"b_nD4nS1.jpg"}

Image is uploading successfuly, i am getting correct response, but not showing, even i tried to alert something, Please help,