JPG, JPEG, JPEG 2000, JPG-LARGE… You probably know these are all different image file formats, but you wouldn’t be wrong for getting them confused with one another. Like many of the most basic functions of a computer or smartphone, it’s one of those things that we’ve seen countless times but might not be able to properly articulate its true meaning. The JPG vs JPEG debate has been raging for decades at this point — sort of like the true pronunciation of GIF — but it actually has a relatively simple meaning. Let’s break down the real difference between JPG vs JPEG.
JPG vs. JPEG: What’s the Difference?
Considering how complex certain files and extensions can be, it might sound shocking to learn that there’s no real difference between JPG vs. JPEG. (Apart from the inclusion or exclusion of the letter E, of course.) At the heart of the issue, the two file formats are exactly the same. One hundred percent identical. No true difference exists between the two aside from the way they’re spelled. Naturally, this raises even more questions than the one we’ve answered already. Most pressing: If they’re the same, then where in the world did that extra “E” come from?
Here’s how JPEG became JPG: Back in 1992, with the release of the latest ISO standards for computing, users were introduced to something called the JPEG. It stood for Joint Photographic Experts Group, and it represented a newfangled technology not often implemented in the tech industry prior: lossy compression. That’s right: at its heart, the JPEG is a bitmap compression format with typical compression ratios ranging anywhere from 10:1 all the way to 20:1. A JPEG’s compression ratio can be adjusted based on both storage size and image quality.
While the JPEG name was initially standardized and released for Windows, Mac, and Unix alike back in 1992, it immediately proved to be a problem specifically for Windows operating systems. The issue was less with the idea of the JPEG and more with the actual name of the format itself. You see, early versions of Windows could only support file formats with three letter extensions, not four. For this reason, the JPG was created. On a Windows OS, a JPG served the exact same purpose as a JPEG — it simply had to have a different name in order to actually fulfill that purpose.
|.jpg, .jpeg, .jpe, .jif, .jfif, .jfi
|Joint Photographic Experts Group
|65,535p x 65,535p
|Joint Photographic Experts Group, IBM, Mitsubishi Electric, AT&T, Canon Inc.
|September 18th, 1992
|Lossy image compression
History of the JPEG
You’re now well aware that JPEG and JPG stand for, and accomplish, the exact same thing. Nevertheless, it’s important to pay attention to their unique histories. The two might be identical in function, but they’re far from identical in terms of usage. The JPEG’s namesake, the Joint Photographic Experts Group, is actually made up of two separate groups: the ISO/IEC JTC 1/SC 29 and the ITU-T Study Group 16. While the JPEG was not officially standardized and defined until 1992, the truth is that this group had been meeting semi-annually since the early 1980s, at least.
Back in 1983, one of the team’s earliest orders of business was to add detailed photo-quality graphics to computer text terminals. Also referred to as a text console (or simply a terminal), these text terminals were a key component of early computers. They were serial computer interfaces designated for text entry and text display, with information manifesting in the form of pre-selected formed characters (a.k.a. character cells). Text terminals were how computers operated at the time, making the group’s work on photo-quality graphics quite significant.
The group’s official formation came in 1986. At this point in time, the team had moved on from their work in the early ’80s and had now begun work on image communication. Here’s another part of our daily technological lives we take for granted: picture messages. Without the work of the Joint Photographic Experts Group, who is to say if we ever could have achieved it? By the time the JPEG standardization came about in 1992, the group had implemented all sorts of existing processes, research papers, and patents to create the digital image compression format we know and love.
Origins of the JPG
When specifying the standards and guidelines for the JPEG back in 1992, the Joint Photographic Experts Group had several preexisting patents they had to rely on. IBM is cited prominently three times, with particular credit paid to their arithmetic coding encoder and decoder system, their free multi-alphabet arithmetic code, and their probability adaptation for arithmetic coders. Mitsubishi Electric is cited prominently twice: Once for their coding system, and again for their coding apparatus and coding method.
AT&T and Canon Inc. were two additional companies that received citations in the 1992 JPEG standardization. Long story short, the Joint Photographic Experts Group went on to show that all of the research was out there, it just needed the right minds to come along and make it make sense. They did exactly that with the creation of the JPEG standards and guidelines. These specifications were embraced and used immediately, with Mac and Unix easily adopting the standard into their existing operating systems. Microsoft, on the other hand, proved to be a problem.
As we briefly touched on above, Microsoft’s operating system was incapable of supporting file formats with four-letter names. All current and earlier versions of MS-DOS needed three-letter names for their file formats. As such, the JPG name was created. The JPG name was adopted by Microsoft all the way back in the early ’90s. As such, it was effectively ingrained in the operating system for good. Though Microsoft can now support four-letter file formats in the present day, they still use JPG because it’s the name Microsoft users have always used.
JPG vs. JPEG: Other Image Formats to Know
While we now know that JPG and JPEG mean the exact same thing, what about those other image formats? JPEG 2000, JPEG XT, JPEG XL, JPEG-LARGE… What are those all about? Let’s briefly discuss these other image formats down below.
Also referred to as JP2, the JPEG 2000 was conceived in the late 1990s as a potential successor to the JPEG format. Developed by the minds behind the original JPEG standards and envisioned as a way to bring JPEG compression to video formats, the file format unfortunately never caught on. While it’s supported by Apple’s Safari, few others are on board with it more than 20 years after its conception.
First launched in 2015, JPEG XT is described as a compression standard that specifies backward-compatible extensions of a standard JPEG. The advantage of this? The JPEG XT supports greater bit depths and higher dynamic range than your standard JPEG. This makes it ideal for today’s 4K UHD-focused world of imaging.
Much like the JPEG 2000, the JPEG XL — first launched in 2017 but not formally standardized until late 2021 and early 2022 — serves as a potential replacement for the standard JPEG. JPEG XL very well could be the next generation of image compression. The new JPEG format improves efficiency and adds support for lossless compression in addition to the traditional lossy compression. Of course, only time will tell whether or not the JPEG XL will take off.
If you’ve ever downloaded an image from Google search results and seen it appear in your Downloads folder as JPEG-LARGE, fear not. This is not some unknown file format. Rather, it’s a way for Google to let users know that the JPEG is particularly large. You can change the extension name from JPEG-LARGE to JPEG manually. You can also run it through another round of image compression yourself.
Pros and Cons of the JPEG
|Pros of JPEG
|Cons of JPEG
|The most used image file format
|No support for animations or opacities
|Almost universally compatible across the web and the tech industry at large
|Original JPEG standard is getting outdated, but newer versions have failed to catch on
|Compressed images retain much of their original color quality
|Lossy compression sometimes hurts image quality
|Fast and easy to create, share, and upload
|JPEG images have no layers
5 Must-Know Facts About the JPEG
- A JPEG is an image file format, but it’s also an abbreviation for Joint Photographic Experts Group.
- The standard JPEG compression algorithm works by calculating the range of colors used and eliminating the ones that the human eye cannot perceive. This process is called lossy compression.
- JPEG can compress an image’s size and colors by as much as 100 to 1. However, it’s much more likely to find a JPEG compressed at a rate of 10 to 1 or 20 to 1.
- JPEGs tend to include metadata about the image such as the time, the date, and even the location the image was taken or created, the settings of the camera, and even a thumbnail preview.
- As the most widely used image file format, it’s estimated that more than several billion JPEGs are created daily.
Is There a Difference Between JPG vs. JPEG?
So, JPG vs JPEG: Is there a real difference? As we’ve seen, the answer is both yes and no. There’s a discernible difference between the word “JPG” and “JPEG,” with the former lacking a letter E. Additionally, there’s a slight difference in use. Windows uses JPG, while everyone else uses JPEG. Technically speaking, however, there is no real functional difference between JPG vs. JPEG. Both are representative of the exact same image file format, no matter which way you ultimately decide to spell it.
The image featured at the top of this post is ©SB7/Shutterstock.com.