It's always hard to get really good screenshots for your game because you generally have to stop playing to take the screenshot. If you're using your iPhone you need to press the two buttons at once, and if you're on a Mac recording in the simulator you need to press Apple-Shift-4-Space then click. It sort of messes up the flow of the game. So I was thinking about how to solve this problem, and I have a great solution. I set up an Automator script thing to take a screenshot, save it to the desktop, rename it with a timestamp, and do this every 10 seconds (easy to change to every 5 seconds or whatever). Then you can just play the game for awhile, and when you're done sift through the dozens of screenshots until you find the best ones. I'd attach my Automator workflow file here, but the TA forums don't let me upload zip files that big (it's 176kb). But let me know if you want it. It's also easy to set up yourself if you play with Automator a little.
or on the mac, you could get some screen recording utility (I use ScreenFlow). They are not very expensive and let you scrub to the exact frame you want to use. This is especially useful when you want to precisely capture an action shot.
Couldn't you add something to your code where if you tap the screen with 2 or 3 fingers at once it will pause, letting you take your time to capture the screen?
We have code in our app that uses the private API UIGetScreenImage for full screen capture on the device. It runs in a timer and saves a screenshot to your photo library every 5 seconds. I uncomment the code when I need new screenshots. It's super simple, doesn't interfere with game play, and captures the screen no matter what is on it. It's even safe to use now: http://www.tuaw.com/2009/12/15/apple-relents-and-is-now-allowing-uigetscreenimage-for-app-st/ Though we still keep it commented out just in case.
on a mac - these already exist - [mac key]+[shift]+[3] for whole screen - [mac key]+[shift]+[3] for selection just run your app on the simulator and you can take screen shots
The problem with even easy keyboard shortcuts, or pausing your game and have the pause dialog disappear, is that it still interupts the flow of the game. You have to take your fingers off the controls for just a second, so you can't get a screenshot in the middle of the action a lot of the time. Having it automatically take screenshots in the background as you play is totally the way to go.