Here are a few simple steps to help you recover your photos from an iPhone backup:
1. Run the iPhone Backup Extractor and Click to Extract Photos
Run the iPhone Backup Extractor and click on the link that shows you the number of photos in your backup (in this case, just 4).
2. Select a Destination Folder for your Recovered Photos
Choose a folder where you'd like the recovered photos to be stored. To keep things simple you may like to create a new folder on your desktop.
3. Click "OK"
Click "OK" to start the recovery process. This should extract the photos from your backup into the folder you selected.
4. Open the Destination Folder
Now open the folder you selected earlier. The photos should be in there. You will need to open folders inside that folder.
5. Find Your Photos
You may have to dig around to find all your photos.
You should now have found your photos!
To get your photos back onto your iPhone you'll need to get them into iTunes, then sync your iPhone with iTunes. Here's a guide to getting photos from your PC to your iPhone.