When dealing with images online and photographs you have probably seen both the JPG and JPEG extensions floating around. Sometimes this can be confusing for people as they don’t know which extension they should be using. Today we want to quickly explain the difference between JPG and JPEG, or if there is one, and what you should be using for your online projects.
JPEG is a file extension that stands for Joint Photographic Experts Group. The ISO standard was originally released back in 1992. It is a bitmap compression format, most commonly used for lossy compression, with compression ratios ranging from 10:1 to 20:1. The compression ratio can be adjusted which means you can determine your own balance between storage size and quality. The JPEG extension is most commonly used by digital cameras and photo-sharing devices.
While the JPEG format is great for color and photographs, it is also important to note that there is a slight loss of quality due to compression. And editing and re-saving only degrade the quality, even though it might be negligible. One way to minimize this is to work with the RAW JPEGs, determine your edits, and then save out the final version without re-saving multiple times.
The MIME media type for JPEG is image/jpeg (defined in RFC 1341), except in older Internet Explorer versions, which provides a MIME type of image/pjpeg when uploading JPEG images. JPEG is also defined with the additional extensions,
Then we have the JPG format. There are actually no differences between the JPG and JPEG formats. The only difference is the number of characters used. JPG only exists because in earlier versions of Windows (MS-DOS 8.3 and FAT-16 file systems) they required a three-letter extension for the file names. So
.jpeg was shortened to
.jpg. While Windows and or DOS had this limitation, UNIX did not and so UNIX and MAC users continued to use the
.jpeg extension. Newer versions of Windows of course now accept more characters in their file extension, however,
.jpg was already being used by a majority of people (and programs needed to work with MS-DOS 8.3) and so it still is the most common extension.
Photo editing programs like Adobe Photoshop and Gimp, all save JPEGs by default to the
.jpg extension, on both Windows and MACs. And if you were wondering, you can change the extension both ways and the file will continue to work.
As you can see, when it comes to the difference between JPG and JPEG, there is none. JPG was simply born out of a limitation that existed by previous versions of Windows and or DOS, and now is actually the most common format, over that of JPEG.