Restore photos to new iPhone from previous backup
There are easy two ways to do this.


You can turn on the iCloud photo library feature in your settings, this will backup your photos to your iCloud account and share them across your Apple devices. You can learn how to do this here: iCloud Photo Library
You can also backup your photos onto a Mac computer as well. This will allow you to easily choose which pictures to put back onto your phone. You can learn how to do this here: Transfer photos and videos from your iPhone, iPad, or iPod touch