A Brief History of the Digital Image

The first permanent photograph in history took roughly eight hours of exposure. Nicéphore Niépce made it in 1826, on a pewter plate coated with bitumen of Judea, pointing his camera out the window of his own house in Le Gras. Today, your phone captures an image in a fraction of a second, processes it, compresses it, and uploads it to Instagram before you've finished putting the phone back in your pocket. Between those two extremes lie about 200 years of history, and nearly every format and technical decision we now take for granted — JPG, the very notion of "file size," even the concept of a pixel — grew out of very concrete problems that someone had to solve along the way.

From silver to light: chemical photography

For more than a century, a photograph wasn't information — it was matter. Silver salts that reacted to light, developed in a darkroom with chemicals that had to be measured by hand. Every print was a unique, or nearly unique, physical object — making a second copy meant re-exposing photosensitive paper under the negative. There was no notion of "compressing" an image, because there was no notion of an image as data: it was metallic silver suspended in gelatin, and its quality depended on chemistry, not an algorithm.

That changed with the arrival of electronic sensors. In 1969, Willard Boyle and George Smith invented the CCD (charge-coupled device) at Bell Labs — a chip capable of turning light into electrical charge, and that charge into a number. For the first time, an image could be represented as a sequence of values. The invention earned them the Nobel Prize in Physics in 2009, four decades later, by which time it was already inside billions of cameras and phones.

The first pixel, and the problem it brought with it

The first scanned digital image in history was made in 1957 at the US National Bureau of Standards, by a team led by Russell Kirsch. They scanned a photo of his three-month-old son onto a grid of just 176×176 black-and-white pixels. That file, tiny by any modern standard, already raised the problem that still defines this field: the more pixels, the more faithful the image — but also the heavier the file. Kirsch had to settle for a low resolution because the hardware of the time couldn't handle more. Seventy years later, we're still making that same trade-off — only now the limit isn't the hardware, it's the weight of the file your website has to load, or the mobile data of whoever's visiting it.

Why JPG exists: the problem wasn't storing the image, it was sending it

By the late 1980s, it was already technically possible to save a photograph as a grid of numbers. The problem was size: a reasonable-quality uncompressed image could weigh several megabytes, and in 1990 that meant minutes of transfer time over a modem, or entire hard drives dedicated to a few dozen photos. In 1992, the Joint Photographic Experts Group (hence the acronym JPEG) published a standard that solved this cleverly: instead of storing every pixel as-is, it exploits the fact that the human eye is far more sensitive to changes in brightness than to subtle shifts in color, and selectively discards the color information that's least noticeable. The result is files up to 10 times smaller with a quality loss that's almost imperceptible to the naked eye. That same principle — deciding which visual information can be discarded without the eye noticing — is still the basis of how images are compressed today, JPG or not.

From camera to pocket: mass digitization

The first consumer digital cameras arrived in the mid-1990s, with resolutions under one megapixel and price tags of several hundred dollars. The real turning point wasn't a camera — it was a phone: the Sharp J-SH04, launched in Japan in 2000, was the first mobile phone with a built-in camera. From there, the curve gets steep — by 2010, most photographs taken in the world no longer came out of a dedicated camera. Today, according to industry estimates, more digital photos are taken in a single day than were shot on film during the entire first decade of the 20th century.

That explosion in volume is why image compression stopped being a technical detail of interest only to engineers, and became something that directly affects anyone with a website, an online store, or simply the urge to share photos without making people wait forever for them to load.

From JPG to WebP and AVIF: the story isn't over

JPG solved the problem of 1992, but today's web has needs that didn't exist back then: transparency with good compression, lightweight animation, and above all, far higher screen resolutions than 30 years ago. Formats like WebP (Google, 2010) and AVIF (2019, based on the AV1 video codec) are the direct continuation of that same pursuit — how to pack more visual quality into fewer bytes — using compression techniques considerably more advanced than those of the 1990s. If you want the technical detail of how they differ and when to use each one, we cover that in the next article.