The business structure to be designed is as follows:

var mySchema = new Schema({
 projectname:  String,
 author: String,
 body:   String,
 task: {
 taskname: String,
 user: String,
 picture: {
 url1,
 url2,
 url3,
 ...
 },
 }
 });

Describing the business structure in words means that each project contains n tasks and n pictures under each task.
Daily operations are
1. new project = > new task = > upload n maps.
2. update project task, etc.

I would like to ask whether my database design is reasonable. Is there a better way? Express development is used.