Access url without token in Firebase Storage

Try changing rule:

service firebase.storage {
  match /b/{bucket}/o {
    match /{allPaths=**} {
      allow read;
      allow write: if request.auth != null;
    }
  }
}

In case you need the rule to allow accessing only the images without a token you have to do the following:

service firebase.storage {
  match /b/{bucket}/o {
    match /{allPaths=**} {
      allow read: if request.auth!=null || resource.contentType.matches('image/.*');
      allow write: if request.auth!=null;
    }
  }
}