If you didn't have iCloud Photo Stream enabled, you do not necessarily need to dig in your iTunes iOS backup files with third-party software.
Just let iTunes restore your iPhone photos back to your iPhone. iTunes automatically backs up your Camera Roll photos each time you sync. As a result, no need to have created an iTunes backup on purpose. Restoring your iPhone with iTunes, however will delete all your current iPhone data and restore your iphone Camera Roll photos, iphone contacts, and settings at the time of the last sync/backup.
As a result, always good to backup before restoring. First, backup your iPhone (right click on your iPhone under devices and click Back Up). To restore from a backup, right click on your iPhone under Devices in iTunes and click Restore from Backup. You can then choose which iPhone backup you want to restore from.