What is the cloud and how does it work: where your photos live, who can see them and what happens when it goes down

The cloud is a set of computers owned by other companies, kept in huge buildings called data centers, that you use over the internet. When you upload a photo to Google Photos or iCloud, it doesn’t float off anywhere: it is copied onto the disks of those machines, and your phone asks for it again whenever you want to see it. You pay for the use, or get some of it free; the hardware and its upkeep are theirs.

Is it safe? That depends on who holds the encryption keys and on your password. Can it go down? Yes: in October 2025 a single Amazon region left thousands of apps offline for hours. And in our test on October 25, 2026, our own website answered in 0.29 seconds from a data center near Washington, D.C.

What is the cloud?

The cloud, or cloud computing, is a way of using storage, software and computing power that sit on someone else’s computers, connected to the internet, instead of on your own device. You ask for what you need when you need it, and the provider takes care of the machines, the power, the cooling and the repairs.

The reference definition is NIST SP 800-145, published in September 2011 by the US National Institute of Standards and Technology. It describes on-demand network access to “a shared pool of configurable computing resources” that can be provisioned and released quickly. It also sets five traits a service needs to count as cloud:

• On-demand self-service: you add space or computing power yourself, without calling anyone.
• Broad network access: you reach it from a phone, a tablet or a laptop.
• Resource pooling: the same machines serve many customers at once, and you usually don’t know which machine holds your data, at most which country or data center.
• Rapid elasticity: the service grows or shrinks with what you use, sometimes automatically.
• Measured service: what you consume is metered (storage, compute hours, users), and that is usually what you pay for.

Where are your Google Photos or iCloud photos, really?

Your photos sit on hard drives inside Google or Apple data centers: buildings full of servers, with backup power and cooling, spread across several countries. Your phone sometimes keeps only a smaller version to save space, but the original stays on those servers, which is why you can also open it from another computer.

Google publishes a map of its data centers, and most of them are in the United States, with others in Europe, Asia and South America. That still doesn’t tell you where your photo is: according to Google’s privacy policy, your information may be processed on servers outside the country where you live.

Free space has a limit. A Google Account comes with 15 GB shared across Gmail, Google Drive and Google Photos, and iCloud gives you 5 GB when you set it up. When iCloud fills up, Apple says new photos stop uploading and your iPhone stops backing up.

How does the cloud work?

Think of the electricity in your home. You don’t have a power plant in the backyard: you plug into the grid, use what you need and pay for what the meter shows. The cloud does the same with computing: instead of buying a server, you use a provider’s and pay per use or by subscription.

What happens when you open a photo stored in the cloud

Where does a web page actually come from? We measured it

On October 25, 2026 we checked with curl, the command-line program that downloads an address and shows its headers, from a home connection in Ecuador. We requested each home page seven times and noted the median total time and what the Server header said, the line where a server introduces itself.

Our site is hosted on Vercel, a cloud platform, and every answer was tagged iad1, which Vercel’s list of regions places in Washington, D.C. The same page says Vercel runs more than 126 points of presence and 19 regions: a nearby point receives the connection and passes it over a private network to the region. The page lives thousands of kilometers away and still arrives in under a third of a second.

The X-Vercel-Cache: HIT header means the page was already waiting in cache, a ready-made copy sent without rebuilding it. That is the trick behind a fast cloud: keep copies of what people ask for most close to them. You can repeat the test by typing curl -I followed by any address.

IaaS, PaaS and SaaS: what’s the difference?

They are NIST’s three service models, and they differ in how much you manage yourself. With SaaS you use finished software; with PaaS you upload your own application and the provider handles everything underneath; with IaaS you rent servers, storage and networking, and install whatever you want on top.

Public, private and hybrid cloud: what’s the difference?

A public cloud is shared by many customers in a provider’s data centers, such as AWS, Google Cloud or Microsoft Azure. A private cloud serves a single organization, whether it sits in its own building or someone else’s. A hybrid cloud joins the two and moves data or apps between them. NIST adds a fourth: community cloud.

What happens if the cloud goes down?

If the data center or region a service relies on fails, that service stops working for you until the provider fixes it or moves the traffic to another region. An outage takes away your access while it lasts; losing files is a separate, rarer risk, and the answer to it is keeping a copy somewhere else.

It happened on October 19 and 20, 2025. According to Amazon Web Services’ own summary, a fault in the automated DNS management of its DynamoDB database left an empty record in the Northern Virginia region (us-east-1). Problems began at 11:48 PM Pacific time on the 19th, and the event wasn’t closed until 2:20 PM the next day.

Whatever hung from that region fell with it. Vercel explained that its iad1 region runs in us-east-1 and that it had to reroute traffic away from it. It’s the same region that answered in our test: the cloud isn’t one place, but every service depends on a few specific places.

Who can see your data in the cloud?

Whoever holds the keys to decrypt it. If the provider keeps them, it can technically read your files and hand them over when a law or a court requires it. If only your devices hold them, which is called end-to-end encryption, not even the provider can open them.

Apple spells it out in its iCloud data security overview: with Standard data protection, the keys to your Photos are kept in Apple’s data centers; with Advanced Data Protection for iCloud, which you turn on in Settings, photos become end-to-end encrypted and only your trusted devices hold the keys. Google’s privacy policy, for its part, says it shares information to meet any applicable law, legal process or “enforceable governmental request”.

The other half is on you. Amazon calls it the shared responsibility model: the provider secures the cloud itself, and the customer secures what they put in it. For your account, that means a unique password, two-step verification and care about who you share an album with.

And not everything has to be uploaded. Some tools do the work on your own device: our document scanner, for example, straightens your photos and builds the PDF inside the browser, without sending them to any server.

What does the cloud change for a small business?

You no longer need to buy and look after a server. Email, invoices, inventory and the website can live in cloud services you pay for monthly or by use, that work from anywhere and grow with you. In exchange, you depend on the internet, on the provider and on its prices.

• Less money up front: a subscription instead of buying hardware that will also age.
• Work from anywhere: check stock or bookings from your phone, at the shop or at home.
• Watch the subscriptions: ten cheap services add up to an expensive bill, and switching is hard if your data is stuck in an odd format.
• No internet, no cloud: if your till depends on it, plan for the day the connection drops.

Your website is the most common case. It lives on cloud hosting, connects to your domain through DNS (we cover how in domains, hosting and DNS explained) and, when it’s set up well, serves cached copies from points close to your customers, as in our test.

The essentials

The cloud is other people’s computers, reached over the internet. It saves you hardware and lets you work from anywhere, but it depends on your connection, on a provider and on who holds the keys: a separate copy and a strong password cover most of the risk.

If what you want to put in the cloud is your business website, at Vertize Business we design it, publish it and leave it running on your domain.

Frequently asked questions