Hey there ekeveny,
Welcome to Apple Support Communities.
Congratulations on your new iPhone 6s! If I understand correctly, you were able to share the photos on your iPhone 4s to your MacBook Pro using iCloud but you aren't seeing those photos on your new device. Take a look at the article below which provides information and troubleshooting tips that may help you recover the missing photos.
Get help finding missing information in iCloud after restoring an iOS device - Apple Support
- Make sure that you correctly restored your iOS device from iCloud. Restoring from an iCloud backup is different than signing in to iCloud. Data stored in iCloud (like your iCloud contacts, calendars, and bookmarks) is pushed to your device when you sign in to iCloud. But to restore your device's local data (like messages and message attachments), you'll need to restore from an iCloud backup.
- Make sure that your information is among the types of information backed up to iCloud.
- Enter your password as needed for apps that require it, like iTunes or Game Center. Some apps need your password before restoring your information.
In iOS 8.1 or later with iCloud Photo Library turned on, your photos and videos are stored in iCloud. They aren’t included in your iCloud backup. After you restore your device, connect to Wi-Fi and turn on iCloud Photo Library by going to Settings > iCloud > Photos. Your photos and videos will begin to download.
If you’re using iOS 8.1 or later and haven’t turned on iCloud Photo Library, or if you’re using iOS 7, iCloud backup includes photos and videos in your Photo Library or Camera Roll. They’ll download to your iOS device when you restore.
- Photos in My Photo Stream are already stored in iCloud, so they aren’t part of your backup. iCloud stores the photos that you uploaded to My Photo Stream for 30 days. To keep these photos on your device and make them part of your backups, save these photos to your Photo Library, Camera Roll, or another album.
- To view a My Photo Stream album, make sure My Photo Stream is turned on in Settings (If you use iCloud Photo Library, the My Photo Stream folder is removed).
- To recover photos that originally synced to your device from your computer, sync your device using iTunes on a computer.
- To restore Photo Library (or Camera Roll) photos to an iPhone or iPod touch, the iCloud backup must be from an iPhone or iPod touch. To restore Photo Library (or Camera Roll) photos to an iPad, the iCloud backup must be from an iPad.
Take care.