Qualitative usability testing aims to identify issues in an interface, while quantitative usability testing is meant to provide metrics that capture the behavior of your whole user population.
90% of data does not get used three months after it’s published. Most Web teams know that they are not working in a professional manner, and yet they feel that there is nothing they can do about it. Digital has in so many ways destroyed content professionalism.
Summary: For mobile navigation, image grids should be saved for deeper IA levels where visual differentiation between menu items is critical, as they increase page load times, create longer pages, and cause more scrolling.