Since iOS allowed saving web pages as icons on the home screen, I've had a link to Hacker News on the first page of apps on my iPhone. iOS looks for an image in a specific location and will use that as the icon for the bookmark. If it can't find one, it'll take a screenshot of the home page.
Since updating to iOS 6, my home screen bookmark icon for Hacker News has started changing to the icons for websites that HN links to. For example, my icon currently is a purple 'Slate' logo after reading a story at Slate.com. The only way to change this is to recreate the bookmark until this happens again.
It'd be great if we could get a HN icon that iOS would use instead of failing to the default and now changing often.
Implementing this is as easy as placing specifically named and sized images in the root directory of the domain.
Specific naming and sizes can be found here: http://gigaom.com/apple/how-to-create-ios-device-home-screen...