Not really answering your question, but in case you did not know, the time and date is automatically saved in your pictures meta data. If you have location services enabled for the camera app you are using, your location is saved as well, as accurately as the iPad can determine it. You can't see this data directly in the Photos app, but if you are running iOS 7 you can see the results of it's use when browsing the Photos tab in the app. The organization by date, events, and location are based on it. Some other apps, including iPhoto will let you see this data more directly by accessing the photograph's info. Now, more to the nature of your question. I don't know of any tweaks, though I suppose there are some. But there are bound to be third party photo apps that will stamp the image (in pixels) with date and time. You don't need a jailbreak tweak for this unless you have to use the native camera app for some reason. I'm afraid I can't recommend a specific app, since I don't' happen to have one with this feature. Good luck.