How can I store my digital photos for ever?

I read your article from June 2016 on What’s the best way to organise and store my digital photos? Is it not sufficient to save my pictures on one external hard drive? Must I save them on two? Also, for how many years will an external hard drive keep the pictures safe?

I have an Apple iMac and until now all my pictures were stored in Photos. Yesterday, I transferred them to an external hard drive and emptied Photos. Is this not enough to ensure the safety and availability of my pics for ever? Arunima

Nothing lasts for ever, and digital images can disappear in seconds. People lose their most important photos every day when hard drives fail, when smartphones and laptops are stolen, when online services shut down, and when natural disasters strike. Fires, floods and earthquakes can also destroy digital records.

To be really safe, you should have more than one copy of each photo, stored in more than one way in more than one place.

Digital data is a particular problem because storage formats change all the time. I still have data on 8in, 5.25in and 3.5in floppy disks, Iomega Zip disks and quarter-inch tapes. The photos might be safe but I won’t know unless I buy something that can read them.

Operating systems, software and file formats also keep changing, so being able to see a file doesn’t mean you can load it. Happily, the standard .jpg/jpeg picture file format developed by the Joint Photographic Experts Group may well last “for ever” despite efforts to replace it with JPEG 2000, PNG (Portable Network Graphics), SVG (Scalable Vector Graphics), SPIFF (Still Picture Interchange File Format), BPG (Better Portable Graphics), FLIF (Free Lossless Image Format), HEIF (High Efficiency Image Format, aka HEIC in Apple’s iOS 11), and Google’s WebP, among others.

Making digital documents last for ever therefore involves two processes. First, you have to keep moving the data to new storage systems before the old one fails or becomes unreadable. Second, you may have to keep converting documents to whichever file format becomes dominant before the old one is abandoned.

Disk drives

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The one thing we know about hard drives is that most of them fail sooner rather than later. Recently, I had a 1TB PC hard drive fail after four years, and a 2TB external USB hard drive failed after seven years. Some drives fail after a few months while others work for a decade or more. There is no way of knowing. However, it’s a good rule of thumb that a drive is increasingly likely to fail after five years or 50,000 hours of use. If you want to keep photos for 50 years, you might have to store them on roughly 10 hard drives in all.

Because a hard drive can fail at any time, it’s not enough to store your photos on a single drive. Two hard drives is a usable minimum, but I have my photos on at least three: my desktop PC, the external USB hard drive that backs up my PC, and an 8TB drive that backs up three external hard drives.
Hard drives are good for storing photos because they are cheap, they provide fast access to data, and it’s very easy to copy a whole hard drive to another hard drive – especially if you have USB 3.0 or Thunderbolt connections.

However, backup drives have their limitations. First, your data is vulnerable both to human error and to malicious software. Second, your data is at risk of being stolen or destroyed by fire, flood or some other disaster.

If your external hard drive is always plugged into your PC, then you can delete whole folders by accident, or by making errors when copying files. If your PC is infected by malware such as ransomware, it will usually encrypt files on external hard drives as well. If a burglar steals your PC, they may take the backup drive as well, and if your house burns down, you’ll also lose both.

You should therefore keep a backup “off site” in the office, or at a friend or relative’s house, or perhaps sealed in a moisture-proof box in a garage or shed.

Optical discs

Because of the risks to hard drives, it’s a good idea to keep backups on removable storage media as well. The current options include CD-R, DVD and Blu-ray optical discs. With optical drives, you should use high-quality discs and store them in a cool, dark and dry place.

Photos on write-once optical discs cannot be deleted by accident, cannot be encrypted or infected by malware, and are unlikely to be stolen. Because they are portable, you can easily store copies off-site.

Unfortunately, a CD only stores 702MB of data, which is great for 100K texts but not so good for 5MB image files. A DVD can store 4.7GB, which is practical for many projects but isn’t big enough for a significant photo collection. For example, you can probably fit all the photos from a wedding or a holiday on one DVD, but maybe not a whole year.

Blu-ray discs can store a lot of data: 25GB on single-layer discs and 50GB on the dual-layer discs used to distribute movies. (Triple- and quad-layer discs are also available.) You can probably fit your whole photo collection on a few dual-layer Blu-ray discs, and 20 will hold a terabyte.

Best of all, you can buy Panasonic Archival Grade or Century Archival Grade Blu-ray discs that are claimed to last for 50+ or 100+ years respectively. These avoid the need to keep copying data to new media, though it’s hard to say how many people will still be using Blu-ray drives in 2120.

USB thumbdrives and SD memory cards are not suitable for long-term archival storage because the charge decays over long periods. Ideally, they should be refreshed every four or five years. You can do that by running the Windows checkdisk command.

Cloud storage

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Storing photos “in the cloud” – basically, on someone else’s collection of hard drives – solves all the problems of using local hard drives and of transferring data to new physical media. But it is important to remember that data in the cloud is not safe and not under your control.

The biggest risks with cloud storage are being locked out of your account, being hacked by someone who deletes all your stuff, and by your account being closed if you don’t pay any charges required. Of course, online storage services may also shut down or go bust, and in one case – Megaupload – the servers were seized by the US Justice Department.

Many large companies offer photo storage services including Amazon, Google, Microsoft (OneDrive), and Apple (iCloud). However, these can be expensive if you need a lot of storage, and your photos will not be as accessible as they are on a local hard drive. Before you commit to making some large uploads, check how easy it is to download files, and whether file-names, sizes and Exif data are preserved.
Flickr offers a terabyte of free photo storage space, with adverts, though it is not as attractive as it used to be. SmugMug is a good alternative and provides unlimited storage for $47.88 a year, after a 14-day free trial period. Microsoft offers a terabyte per user with Office 365, with Personal (one user) priced at £59.99 a year and Home (five users) at £79.99. Amazon offers unlimited photo storage if you pay £79 a year for Prime membership.

Be careful of services that don’t preserve your original photos exactly as you uploaded them. Google charges £7.99/$9.99 per month to store a terabyte of photos at their original quality, but will store them free at a reduced (16MP) resolution that it, correctly, calls High Quality. Facebook’s photo storage is free but it reduces images from printable quality to web-viewing quality.

There are many alternatives, but the largest players – Amazon, Apple, Facebook, Google and Microsoft – are most likely to be around in the long term. Of course, prices and terms may change, and if you store photos for 50 or 100 years, the cost adds up.

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