In fact, when a file deleted from your Samsung Galaxy S, it is not really deleted. The operating system only removed it from the file directory in the folder and flagged the storage of the deleted file as being available for overwritten. That is why you can not find them even it still exists on your phone. So, before you shooting some new photos and video to overwrite the memory, you can fully retrieve deleted pictures from Galaxy s phone with a Samsung Galaxy recovery software.
You can choose EaseUS MobiSaver for Android.
1.Connect your Galaxy S phone to computer
Install and run EaseUS MobiSaver for Android and connect your Galaxy S2 to the computer with USB cable. Then click "Start" button to begin the Samsung Galaxy recovery job.
2.Scan Galaxy S phone to find deleted photos
In this step, EaseUS MobiSaver for Android can connect and scan your phone to find and analyzed all the data. After scanning, the software can classified the found data into different categories, for example, "Contacts", "Messaging". So you can easily find the files you want to get.
3.Preview and restore deleted photos from Galaxy S2
Details steps you can watch the video https://www.youtube.com/watch?v=wP9ogGVjmhw