iPhone 4 gets iOS4.1 HDR, Soon to arrive on Jailbroken iPhone 3GS and 3G.
iOS 4.1 has brought some new features to the iPhone 4 and one of them is arrival of HDR (High Dynamic Range) photography from your iPhone 4. The new HDR features allows you to take much more detailed pictures/photos than normal camera photos. The basic principle of HDR is that it takes three individual pictures with in a few seconds (one properly exposed, one overexposed and one underexposed) and after taking the pictures, Joins those three to give a single detailed photo, hence making it better than normal photography mode.
iPhone 4 comes with a 5 Mega Pixel camera so this feature is better suited for it only, But this iPhone 4 exclusive feature may soon arrive on your Jailbroken iPhone 3GS and 3G just like the other iPhone 4 features such as wallpapers and multitasking.