JPEG Image (.JPG): Structure & Safe Inspection

Check supported header evidence locally. Identification is not file validation or a malware scan.

Quick facts

Extension

.jpg, .jpeg

Format

JPEG Image

Category

image

MIME type

image/jpeg

Standard / developer

ISO/IEC and ITU-T

Open with

ImageMagick identify

What is JPG?

Every JPEG bitstream begins with the Start of Image marker FF D8. Bytes after that marker distinguish structures such as JFIF APP0 or Exif APP1; a longer JFIF signature must not be required for every JPEG.

• Store and exchange compressed photographic images

How to open JPG

ImageMagick format support can depend on its build and delegates; check the local format list before relying on this workflow.

Technical details

Signature

FF D8 (JPEG Start of Image)

Encoding

Not applicable

Container

JPEG marker stream; commonly JFIF or Exif-oriented

Compression

Usually lossy JPEG coding; the family also defines lossless processes

JPEG File Interchange Format family

Things to check

• Repeated lossy editing can introduce further degradation; JFIF-specific bytes are not universal to every JPEG wrapper.

Related formats

• Portable Network Graphics

  PNG is a lossless raster alternative with a chunk-based structure and different transparency workflow.

• WebP Image

  WebP is a RIFF-based alternative that can store lossy or lossless image data.

• AV1 Image File Format

  AVIF uses ISO Base Media File Format structures and AV1 coding, while JPEG uses the JPEG codestream family.