What's the difference between .jpeg/.jpg/.JPG ?

[Hae Yun Jung]

Yeah I know it's a funny question.

Until now I didn't feel much of a difference between these 3 formats.

But like this, you can see jpg, JPG, JPEG.

This means that Adobe knows the difference between these three.

I tried to google it, but I couldn't find a good answer.

Plz help me

[lesliewand]

The only difference between JPEG and JPG, if at all, you can call it that is the number of characters used. JPG still exists because earlier versions of Windows/DOS systems required a three letter extension for file names. Hence, .jpeg was shortened to .jpg. Now, Windows supports extension with four characters. Hence, you can open .jpeg files on Windows.

Unix and Mac systems did not have this limitation of characters. They continued to use the .jpeg format.

Your photo-editing applications like Adobe Photoshop, Gimp save JPEGs to the .jpg extension. You have the liberty to change the file extension both ways and the file continues to work. Unlike JPEG, JPG preserves the image quality of the file with less data redundancy after compression. Hence, JPG files take up more space. As JPG files also use lossy compression algorithm, image quality deteriorates with the decrease in file size.

[D Fosse]

lesliewand   wrote

Unlike JPEG, JPG preserves the image quality of the file with less data redundancy after compression.

To avoid confusion here: Jpeg is a specification, not an extension. The specification accepts a number of interchangeable extensions including jpg/jpeg/JPG/JPEG and several others. You can rename the extension and the file will still open normally, as long as you use one of the standard allowed variants.

If any application imposes restrictions on this, it's not complying with the jpeg specification.

The compression is part of the specification and has nothing to do with the extension.

[Test Screen Name]

Bear in mind this dialog is not choosing a file format only. It is also choosing an exact name to suit your preferences. If someone's files are called wilma and barney, they will want wilma.jpg and barney.jpg. If their files are called FRED and BETTY they will want FRED.JPG and BETTY.JPG. The file is the same either way.

[gener7]

Generally, you should not use JPG upper case file extensions.  Some servers will not read them and you won't be able to see the pictures until you change the extension to lower case jpg.

[jane-e]

Hi

Here’s what you didn’t ask, but I’m sure you want to know:

JPEG is an acronym for Joint Photographic Experts Group

Here’s their website: https://jpeg.org/about.html

Jane