Did you try to restore from a backup taken before you erased the phone? If you don't use the iCloud Photo Library, Photos are part of the backup:
Cloud automatically backs up the information on your devices—iPhone, iPad, and iPod touch—over Wi-Fi every day when they are turned on, locked, and connected to a power source. With your device information backed up in iCloud, you can easily set up a new device or restore information on one you already have.
Here’s what iCloud backs up:
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- Photos and videos on your iOS devices, unless you turn on iCloud Photo Library beta on your iOS 8.1 device. If you turn on iCloud Photo Library beta, your photos and videos are already stored in iCloud, so they aren’t included in your iCloud Backup.
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copied from iCloud: iCloud storage and backup overview