Store offline image on ionic storage

Hello, I created an application with a simple user registry and storing in ionic storage, but I would like to know how to store an image to be the user's profile photo

My Provider looks like this:

import { Injectable } from '@angular/core';
import 'rxjs/add/operator/map';
import { Storage } from '@ionic/storage';
import { DatePipe } from '@angular/common';

@Injectable()
export class ContactProvider {

  constructor(private storage: Storage, private datepipe: DatePipe) { }

  public insert(contact: Contact) {
    let key = this.datepipe.transform(new Date(), "ddMMyyyyHHmmss");
    return this.save(key, contact);
  }

  public update(key: string, contact: Contact) {
    return this.save(key, contact);
  }

  private save(key: string, contact: Contact) {
    return this.storage.set(key, contact);
  }

  public remove(key: string) {
    return this.storage.remove(key);
  }

  public getAll() {

    let contacts: ContactList[] = [];

    return this.storage.forEach((value: Contact, key: string, iterationNumber: Number) => {
      let contact = new ContactList();
      contact.key = key;
      contact.contact = value;
      contacts.push(contact);
    })
      .then(() => {
        return Promise.resolve(contacts);v  b 
      })
      .catch((error) => {
        return Promise.reject(error);
      });
  }
}

export class Contact {
  name: string;
  lastname: string;
  password: string;
  phone: number;
  birth: Date;
  active: boolean;
}

export class ContactList {
  key: string;
  contact: Contact;
}