Is there a difference between .JPG and .jpg?

Question

Files that have uppercase extensions (specifically .JPG) are not opening or being recognized in Windows Live Photo Gallery. .jpg files work as expected. What could be causing this issue?

Solution

Windows' file access is (generally) not case sensitive. Most Windows programs should not care. Most likely, the two 'different' extensions are from different sources, and the source of the .JPG files has them in an odd/corrupted format.

For example, you have two cameras. One names its files .JPG, the other names them .jpg. The files coming from the first camera could be corrupt. The naming is not the issue, the source (or specific file itself) is.

It should be noted that the actual file system is case preserving (see comments below). It should not make any difference except in a small set of specialised applications - which does not include Windows Live Photo Gallery.

Comments

[Admin]

What happens if you rename a .JPG file to .jpg, or the other way around?

[akira]

en.wikipedia.org/wiki/NTFS : ntfs is case sensitive .. IF you use the right namespace.

[Joachim Sauer]

@akira: in practical usage NTFS is case preserving, but is almost always accessed in a case-insensitive manner.

[akira]

@JoachimSauer: yep, but why do you explain that to me? :) especially when your argument makes it clear that it's the APPS which are 'doing it wrong' and not the 'windows file system'.

[Joachim Sauer]

@akira: I was trying to relativize your statement: NTFS might be case sensitive on a low level, but in practical application this almost never shows an effect.

[akira]

exactly. so it's good to address that in the answer :)