I check Storrium from my iPad and made a homescreen shortcut for it. I get a bland screenshot of the page as the icon because there's nothing else set (I assume, maybe wrongly).

If you haven't, I'd recommend adding the code from the following URL to make these homescreen shortcuts use the Storium logo:

https://developer.apple.com/library/ios/documentation/AppleApplications/Reference/SafariWebContent/ConfiguringWebApplications/ConfiguringWebApplications.html

Cheers,

Tim