Via Parametric Press, JPEG images are everywhere in our digital lives, but behind their familiarity lie algorithms that remove details that are imperceptible to the human eye. This process produces the highest visual quality with the smallest file size—but what does that look like? This article shows you with live changes to images.
By the early 1980s, computers could store and display digital images, but there were many competing ideas about how best to do that. You couldn’t just send an image from one computer to another and expect it to work.
To solve this problem, the Joint Photographic Experts Group (JPEG), a committee of experts from all over the world, was established in 1986 as a joint effort by the ISO (International Organization for Standardization) and the IEC (International Electrotechnical Commission)—two international standards organizations headquartered in Geneva, Switzerland.
JPEG, the group of people, created JPEG, a standard for digital image compression, in 1992. Anyone who’s ever used the internet has probably seen a JPEG-encoded image. It is by far the most ubiquitous way of encoding, sending and storing images. From web pages to email to social media, JPEG is used billions of times a day—almost every time we view or send images online. Without JPEG, the web would be a little less colorful, a lot slower, and probably have far fewer cat pictures!
This article is about how to decode a JPEG image. In other words, it’s about what it takes to convert the compressed data stored on your computer to the image that appears on the screen. It’s worth learning about not just because it’s important to understand the technology we all use everyday, but also because, as we unravel the layers of compression, we learn a bit about perception and vision, and about what details our eyes are most sensitive to.
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