Photo in icloud

If you have a "Camera Roll", you do not have iCloud Photos turned on in your phone. See: Set up and use iCloud Photos - Apple Support

If you have iCloud Photos turned on, the photos on the device are the same as on iCloud, with the possible exception that some of them may be space-saving optimized versions if you have that option turned on. You view them in the Photos app on an iOS device. You can also use a computer and login to icloud.com and go to the Photos app there. See: https://support.apple.com/en-us/HT204264

If you didn't have iCloud Photos turned on but do have an iCloud backup, you can restore the entire phone (not just the photos) from iCloud but you cannot otherwise view the contents of the backup. https://support.apple.com/kb/ph12521

Here's how it works

iCloud Photos automatically keeps every photo and video you take in iCloud, so you can access your library from any device, anytime you want. Any changes you make to your collection on one device, change on your other devices too. Your photos and videos stay organized into Moments, Collections, and Years. And all of your Memories and People are updated everywhere. That way you can quickly find the moment, family member, or friend you're looking for.

Your collection uploads to iCloud each time your device connects to Wi-Fi and your battery is charged. When you have iOS 11 or later, your library updates over cellular too. Depending on your Internet speed, the time it takes for you to see your photos and videos on all of your devices and iCloud.com might vary.

Before you begin

1. Update your iPhone, iPad, or iPod touch to the latest iOS, your Mac to the latest macOS, and your Apple TV 4K and Apple TV HD to the latest tvOS.
2. Set up iCloud on all of your devices.
3. Make sure that you’re signed in to iCloud with the same Apple ID on all of your devices that you want to use with iCloud Photos.
4. If you have a Windows PC, update to Windows 7 or later and download iCloud for Windows.

Turn on iCloud Photos

• On your iPhone, iPad, or iPod touch with iOS 10.3 or later, go to Settings > [your name] > iCloud > Photos, then turn on iCloud Photos.
• On your Mac with OS X 10.10.3 or later, go to System Preferences > iCloud. Click Options next to Photos, then select iCloud Photos.
• On Apple TV 4K and Apple TV HD with tvOS 9.2 or later, go to Settings > Accounts > iCloud > iCloud Photos.
• On your Windows PC, follow these steps.

In earlier versions of iOS, macOS, tvOS, and iCloud for Windows, iCloud Photos was called iCloud Photo Library.

See your edits on all of your devices

When you make edits in the Photos app on your iOS device or your Mac, the photo automatically updates across all of your devices. So when you crop or enhance a photo from your iPhone, you see the changes when you access your library from your Mac. If you change your mind and want to revert to the original view, it's no problem. The original photos and videos are stored in iCloud and you can go back to them at any time.

Even the photos and videos you delete on one device, delete everywhere that you use iCloud Photos. And if you want to get a photo back, you can restore it from the Recently Deleted album for 30 days.

You can make edits on your iPhone, iPad, iPod touch, or Mac, and you’ll see them on your Apple TV automatically. Your entire collection is available on Apple TV, including your Memories and shared albums.

File types that you can use with iCloud Photos

Your photos and videos are stored in iCloud exactly as you took them. All of your images are held in their original formats at full resolution — HEIF, JPEG, RAW, PNG, GIF, TIFF, HEVC, and MP4 — as well as special formats you capture with your iPhone, like slo-mo, time-lapse, 4K videos, and Live Photos.

Set up and use iCloud Photos - Apple Support

https://support.apple.com/en-us/HT204264

If they are in iCloud, they are not on your Camera Roll. And if they are on your Camera Roll, they are not in iCloud.

Check Settings > Photos > iCloud Photos to decide where you would like to house them.