My iPhone 4S won't restore from backup data?

I backed up my iPhone in February. I don't know what iOS it was running (probably iOS 6, 6.0.1, 6.0.2, 6.1). Now it's running iOS 6.1.3 and I'm trying to restore it to get back my pictures on there, but when the wasted 30 minutes have passed I get a pop-up on iTunes saying that the iPhone can't be restored. Do I need to downgrade my iPhone to the iOS it was running when I backed it up?

Try restoring with your anti virus turned off sometimes it blocks apple severs.
you can't downgrade a 4S

It is too trouble to downgrade iPhone to the iOS. Actually, with iPhone backup restore data recovery program, you can easily to get your pictures backup. If you are searching for more information, you are able to google search " any data recovery".