Many people love taking photos with iPhone, and for kinds of reasons you would lost your love photos. But we can still recover them as long as you've made a backup in iTunes before, and I think it's easier to use an iPhone data recovery app to help.

Try Coolmuster Data Recovery (for PC/Mac), it's high quality and easy to use.
Don't know How to recover iPhone photos on computer, just follow this guide.

Remember don't connect your iPhone to computer, or the iTunes backup file will be updated.

Step 1: Select Backup Device
Launch the iPhone backup extractor, then app would retrive all ios devices that you have backuped on the computer before, and select your previous iPhone backup files from the list. Next, click "Start Scan", the problem will scan and display all the contents contained in the backup files.

Step 2: Recover photos from iPhone backup
Just like the image below shows, you can click the icon to preview the photos. Then select and check those photos you want extract from the right. At last, click "Recover" to start the extract.

Great, that's all!
Resource:
http://www.coolmuster.com/ios-recovery/recover-deleted-photos-from-iphone.html