iOS 4.1 HDR indicator

iOS 4.1 keeps both HDR and regular versions of photos by default (you can disable that behaviour in Settings.app -> Photos, in which case it'll discard the regular version of any HDR photos you take).

 

When you're browsing your photos via Photos.app, you can see which ones are HDR versions by the HDR badge applied to the top-left (it's just an overlay in Photos.app, and it disappears if you hide the navigation/toolbars).

Done