It's very simple. I've started using app tabs, and my first three are fine. Now I've created an app tab from my tab to the website http://www.thomasyoungcentre.org/index.html. However, its app tab only appears as a white page, which isn't very memorable, especially as I find that some other websites I use have the same blank app tab. So I wonder if I can make a little custom icon of some kind to identify this website for me on its app tab. Alternatively, what do I need to tell the website managers that will enable this feature for us.