pictures.ts

// The pictures I'm guessing are in Firebase Storage, but they need to be linked (through the download URL) to the database, 
// so something like:

userProfile: {
  user1: {
    name: "Jorge",
    profilePicture: "https://link_to_picture"
  }
}

// So to cath them you need to make a Firebase call:

firebase.database().ref("userProfile").on('value', profileListSnapShot => {
  // Somewhere in your page you should have a profile list variable declared, we're going to use it here:
  let tempList = [];
  profileSnapShot.forEach( snap => {
    tempList.push(snap.val());
    return false;
  });
  this.profileList = tempList;
});


// Then in the HTML you can call the list:

<ion-list>
  <ion-item *ngFor="let profile of profileList">
    <h2>{{ profile?.name}}</h2>
    <img [src]="{{ profile?.profilePicture }}" />
  </ion-item>
</ion-list>