One of the most common image formats is JPG or JPEG. But is there a difference between these two terms?
Cute cat photos or a quick snap of a delicious meal in the restaurant – social media is full of such pictures. With a smartphone, it only takes a few seconds and the best memory ends up on the memory card or in the cloud forever. If you actually go to the trouble later and look through your pictures properly, you are guaranteed to come across the file extension “.jpeg” or “.jpg” very often. This is the most common image format. In this article we will explain why this is so and why there are two endings for an image format.
First of all, JPEG is an abbreviation for “Joint Photographic Experts Group”. This international organization developed the JPEG image format in 1992. Since the official name ISO/IEC 10918-1 standard or CCITT Recommendation T.81 sounds a bit cumbersome, the members simply choose the name of their own organization: JPEG.
Why is JPEG such a popular image format?
To understand why JPEG has become a universal image format, let’s go back to the early days of the computer industry. In the 1980s there were already computers with a graphical user interface. However, photos are difficult to display on the early computers.
That is why standardization experts put their heads together to create a suitable image format. The JPEG has the edge in this respect. The JPEG image format makes it possible to display photo-realistic images on monitors that were common at the time.
This works because JPEG uses lossy compression. What does that mean? Certain areas are removed from the original image. However, these are very small and therefore not visible to humans. These tiny ‘holes’ or pixels are filled with dots of colour. Thus, when viewed on the screen, the image looks like the original.
However, it is only a compressed copy. And now comes the catch: A JPEG image can only be enlarged to a limited extent. That’s the price of lossy compression. But that doesn’t matter, because the advantages outweigh the disadvantages.
JPEG only for photo amateurs?
Of course, even in the digital age, professional photographers prefer to use uncompressed image formats. These are best edited later.
However, professionals also like to use the JPEG image format because of the small file size. Compression makes it easy to send images as email attachments. JPEG is perfectly fine for viewing on a screen.
In addition, the JPEG image format stores information such as the location of the picture or the time of the picture, the so-called Exif data. This will help later when assigning the images.
JPEG also offers a lot of advantages for websites. Because the format cannot be enlarged at will. The degree of compression can be set manually for this. This is useful if a large number of photos are to be displayed on a website. This reduces the loading time of the page.
By the way: If you use the free image editor GIMP, the software asks for compression before exporting to JPEG format. You can also check whether the Exif data, the preview or the color profile should be saved, for example.
What is the relationship between JPG and JPEG?
To stay with the metaphor: JPEG and JPG are one and the same format. The omitted ‘E’ dates from the early days of the computer age. Before operating systems like Windows got a fancy, graphic user interface, the complete control ran via the DOS level. This in turn only recognizes file extensions with three letters.
The JPEG organization has dispensed with the ‘E’ so that JPEG images can also appear on the screen on old computers. This ending has survived to this day. Most JPEG images end up on the computer as “.jpg”.
There are other formats of these DOS relics, for example HTM or HTML, MPG or MPEG as well as TIF or TIFF. However, there is actually a whole JPEG family. Well-known offshoots include JPE or JFIF or in DOS format: JIF.