read-metadata

Read Image Metadata

Extract metadata from image files using exiftool and output as structured JSON. Supports single files, batch operations, and filtering by metadata group (EXIF, IPTC, XMP, GPS, etc.).

When to use

• Inspecting the metadata on a photo before sharing or publishing.
• Auditing a batch of images to verify copyright, GPS, or camera information.
• Programmatically querying metadata for file organization or validation.

Inputs to gather

• Input file or directory — single image or folder. Default: current directory.
• Recursive? If directory, ask whether to descend. Default: no (flat).
• Filter/group (optional) — ask if they want a specific metadata subset (e.g., EXIF only, GPS only, copyright-related tags). Default: all metadata.
• Output format — JSON (default) or a human-readable summary. Recommend JSON for programmatic use, summary for quick inspection.

Procedure

1. Check tooling

command -v exiftool || echo "exiftool not installed — install with: sudo apt install libimage-exiftool-perl"

Abort if missing.

2. Determine scope

• Single file: direct read.
• Directory (non-recursive): read all image files in the folder.
• Recursive: use find to walk the tree.

3. Read metadata

Single file, full metadata as JSON:

exiftool -j "<file.jpg>"

Single file, summary (human-readable):

exiftool -G1 -a -s "<file.jpg>" | head -50

Filtered by group (EXIF only):

exiftool -j -G1 -EXIF "<file.jpg>"

Common filters:

• -EXIF — EXIF metadata only.
• -IPTC — IPTC tags (description, keywords, copyright).
• -XMP — XMP metadata (structured, often used by Adobe).
• -GPS — GPS coordinates (latitude, longitude, altitude).
• -MakerNote — camera-specific metadata.

Batch (directory or recursive):

find <target> -maxdepth <1|999> -type f \
  \( -iname '*.jpg' -o -iname '*.jpeg' -o -iname '*.png' \
     -o -iname '*.heic' -o -iname '*.webp' -o -iname '*.tif' \) \
  -exec exiftool -j {} \; > metadata.json

4. Summarize or display

For JSON output:

If the user wants a summary, parse the JSON:

exiftool -j "<file.jpg>" | jq '.[] | {File, Make, Model, DateTime, GPSLatitude, GPSLongitude, Copyright}'

For a batch report:

exiftool -j -a -s "<target>/*" | jq '.[] | {FileName, Make, Model, LensModel, FocalLength, ISO, ExposureTime, FNumber}'

5. Report

Print the metadata (JSON or summary, per user preference). If batch:

• Count of files read.
• Any files with missing metadata.
• Common metadata patterns (e.g., "15 images from Canon EOS 5D Mark III", "8 images missing GPS").

Output / side effects

• Metadata displayed on stdout (or saved to a JSON file if requested).
• No files modified.

Notes

• Metadata standards overlap: EXIF, IPTC, and XMP sometimes describe the same field (e.g., copyright, description, keywords). exiftool -j merges these intelligently; check the JSON keys to see what's present.
• Camera-specific tags: Each camera manufacturer (Canon, Nikon, Sony, etc.) embeds maker-specific metadata. Run with -MakerNote to inspect.
• GPS privacy: Check for -GPS tags before sharing a photo. Many smartphone cameras and some cameras embed GPS by default.
• Phone metadata: iPhones embed extensive metadata in EXIF and XMP, including model, iOS version, and processing applied.
• PNG text chunks: PNG metadata lives in text chunks (tEXt, iTXt) rather than EXIF. exiftool reads them as XMP or PNG metadata.
• Batch JSON: Combine multiple JSON objects with jq -s '.' output.json to create a single JSON array for programmatic processing.
• Depends: apt install libimage-exiftool-perl.