This question is part of the Experiments section in tutorial 8 of the AngularJS tutorial.
Here is how I solved it. I took the different road of counting the images rendered rather than testing the repeater/model directly.
it('should display four thumbnails of the nexus-s', function() {
var imgsCount = element.all(by.css('.phone-thumbs li img')).count();
expect(imgsCount).toBe(4);
});