There mainly are two methods to retrieve lost or deleted data.
Part 1: Directly Restore Lost Data Files from iPhone 4 Device
First of all, download the right version of iPhone Data Recovery. Install it on your computer and run it.
Step 1 Connect your Device to the Computer
Connect your iPhone 4 to the PC with a USB cable. The interface will be shown as follow. Select "Recover from iOS device" in the window and you'll be informed that your device is connected. Then click "Start" and continue.
Step 2 Wait for the Analyzing
Your device will be analyzed by the iPhone 4 data recovery. The analyzing process will last for some time, wait patiently now.
Step 3 Scan for Lost Data Files
When the analyzing process finishes, the program will start scanning for lost or deleted data files for you automatically. You can see the process and remaining time from the progress bar. Wait for the scanning results now.
Step 4 Preview and Check Lost Files to Recover
After the scanning, you will get the results listed in categories on the left in the window, such as "Camera Roll", "Photo Stream", "Contacts" and so on. Go to each icon and expand it. Preview the details and check those you want back. Click on "Recover" button to save them on your computer, thus all deleted or lost data coming back to your life.
Part 2: Scan and Extract iTunes Backup File to Restore iPhone 4
This way works well if you have synced your iPhone device with iTunes before.
Step 1 Run iPhone Data Recovery on the PC
Download and install the program on your computer. Launch it and you will get the following interface. Navigate to "Recover from iTunes Backup File" and you can see all your previous iDevices' backup files are listed in the window. Select your device name and click "Start Scan".
Step 2 Preview, Check and Recover
When you get the scanning results after some minutes, go to each file category and preview the details. You can go to "Camera Roll" and "Photo Stream" as well as "Photo Library" for lost pictures. Also, you can turn to "Messages" to find your deleted SMS. Check all you want to get back and click "Recover". All of them will be restored on your PC then.
How to Recover Lost Data from iPhonehttp://www.iphone-data-recovery.com/rec ... phone.html
How to Recover Deleted Photos from iPhonehttp://www.iphone-data-recovery.com/rec ... hotos.html
How to Recover Deleted SMS from iPhonehttp://www.iphone-data-recovery.com/rec ... phone.html
How to Recover Lost or Deleted iPhone Contactshttp://www.iphone-data-recovery.com/rec ... phone.html