First, double-tap the more info button. Second, turn VoiceOver off, and then tap the screen one time. (You can do this anywhere, as long as you tap the screen once.) Third, turn VoiceOver on and tap the upper right side of the phone near the earpiece--my friend says that it is "the top right corner." VoiceOver should indicate that you tapped the action button, which at that point should work for you. When you double tap the action button, tap once on the screen--regretably, flicking does not work. After you tap once, you should hear VoiceOver announce one of the options specific to the action screen. When one of these options is announced, simply flick left and right to move through each one.
—http://www.applevis.com/applevis-forum/ios-ios-app-discussion/saving-photos-text-messages
This is the process for interacting with an image inside a text message in VoiceOver, thanks to a particularly nasty iOS 6 bug. The bug leaves you on a “blank” screen, after tapping into the image. No “back” button read aloud—no navigation, no way of getting your bearings.
Imagine iOS 6 shipped with a bug where tapping on an image in a text message turned off your screen. And seriously, as assisitive tech for mobile goes, VoiceOver is as good as it gets.
It ain’t a good scene. Work hard; build accessible websites. We gotta raise the bar, here.