The only problem is that rooting and iinstalling an app writes to internal storage - so a couple of the deleted pictures could become corrupted (and there's no other way - which is why all important files should be backed up to at least one other device).
Rukbat, You Are Right. So To Make Sure This Doesn't Happen Again I Would Get Google Photos. But You Probably Already Have Google Photos. So (If You Ever Set It Up) Go There To See If Those Photos Were Ever Backed Up.