Image Format Comparison

JPG vs JPEG: What is the Difference?

JPG and JPEG are exactly the same format. There is no technical difference whatsoever — they contain identical data, use identical compression, and are interchangeable in every context. The only reason two extensions exist is historical: early Windows (MS-DOS) limited file extensions to three characters, so the four-character .jpeg extension was shortened to .jpg. Unix and Mac systems always allowed .jpeg. Both extensions remain common today.

JPGvsJPEG

Quick Verdict

Use JPG when…

Use .jpg — it's shorter and more common. Windows, macOS, and most cameras default to .jpg. Most web servers serve both identically.

Use JPEG when…

Use .jpeg if a specific tool, CMS, or API explicitly requires it, or if you're on a system that historically used .jpeg. The file content is identical.

JPG vs JPEG: Feature Comparison

Feature	JPG	JPEG
File format	JPEG compression	JPEG compression (identical)
File content	Identical to .jpeg	Identical to .jpg
Extension length	3 characters (MS-DOS compatible)	4 characters
Camera default	Most cameras use .jpg	Some cameras use .jpeg
Web standard	More common on the web	Less common but valid
macOS default	Preview saves as .jpg	Some tools use .jpeg
MIME type	image/jpeg	image/jpeg (same)
Can rename safely?	Yes — renaming .jpg to .jpeg is safe	Yes — renaming .jpeg to .jpg is safe

When JPG wins

✓File format: JPEG compression
✓File content: Identical to .jpeg
✓Extension length: 3 characters (MS-DOS compatible)

When JPEG wins

✓File format: JPEG compression (identical)
✓File content: Identical to .jpg
✓Extension length: 4 characters

Frequently asked questions

Can I rename .jpg to .jpeg or vice versa?

Yes — completely safe. The file extension is just metadata; the actual image data inside is identical. Rename .jpg to .jpeg or .jpeg to .jpg freely with no effect on quality or compatibility. Your OS may warn you about changing the extension, but the file will open correctly.

Why does my camera save as .JPG instead of .JPEG?

Cameras inherited the .jpg convention from the MS-DOS era of the 1990s, when three-character extensions were the rule. The convention stuck. Every camera manufacturer uses .jpg as the default. .jpeg is equally valid and contains identical data.

Does a web server care if an image is .jpg or .jpeg?

Not for serving the file — both extensions serve with the image/jpeg MIME type. However, case matters on Linux servers: photo.jpg and photo.jpeg are two different files. Make sure your HTML references the correct filename and extension, and be consistent in your naming convention.