Tonight, Apple has released the second beta revision of its iPhone OS mobile operating system. iPhone OS 4.0 (Beta 2) with a build number of 8A248c and weighing in at 355 MB, hit Apple servers about an hour ago now – and if you thought beta 1 was bad, think again ..

As first reported by @Viticci, this new beta sees the introduction of a few welcomed changes and fixes, all of which, as always, are under strict NDA. If you’re a developer though, you can head on over to this page to check them out for yourself.

There is one problem. This beta has quite a rather large bug. Photos.app is dead. Unfortunately, iPhone OS 4.0 Beta 2 doesn’t allow you to save screenshots or images to Photos.app. In addition, this version also breaks saving photos with Camera.app to your camera roll and importing them with iPhoto.

Intentional? .. Probably. There is however a workaround. As noted by @TUAW, you can simple take screenshots with Xcode, and import them into iPhoto that way.

This post will be continually updating with information about the new beta. Stay tuned!