For storing the image of the master product, we will be assigning a special data type to the image attribute of the MasterProduct entity. That special data type is Transformable data type. So, let us have an idea of that data type before we move further.
The Transformable data type is a special data type that allows us to create attributes based on an Objective-C class (custom objects). This data type is heavily used for storing instances of UIImage, UIColor, and so on. As the information stored in the persistent store has to be in the form of NSData instance, while using Transformable data type, we need to create Value Transformers to convert the custom object (information in attribute of Transformable data type) into an instance of NSData (before storing in the persistent store) and to convert the instance of NSData back to custom object while retrieving from the persistent store.