Write Metadata to Images

Set metadata tags on image files using exiftool. Supports EXIF, IPTC, and XMP metadata, with automatic backup of original files.

When to use

• Adding copyright and artist information to a photo before distribution.
• Manually setting GPS coordinates if they were not captured.
• Batch-updating descriptions or keywords across multiple images.
• Fixing incorrect camera model or lens metadata.

Inputs to gather

• Input file or directory — single image or folder.
• Metadata key-value pairs — ask the user for the tags and values they want to set. Common fields:
  • Artist — photographer or creator name.
  • Copyright — copyright statement (e.g., "© 2026 Daniel Rosehill").
  • Description / ImageDescription — image description text.
  • Keywords — comma-separated keywords.
  • LensModel — lens description (if not auto-detected).
  • GPSLatitude / GPSLongitude / GPSAltitude — GPS coordinates.
  • DateTimeOriginal — capture date/time (format: YYYY:MM:DD HH:MM:SS).
• Backup before write? Default: yes. exiftool creates _original sidecars; offer an explicit backup copy for safety.

Procedure

1. Check tooling

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

Abort if missing.

2. Validate tag names

Ask the user to confirm the exiftool tag names. Common mappings:

Gotcha: EXIF, IPTC, and XMP may use different tag names for the same logical field. exiftool auto-detects the appropriate target; document which format will be used:

exiftool -a -G1 "<sample.jpg>" | grep -i copyright

This shows which groups (EXIF, IPTC, XMP) currently carry copyright info on the sample file.

3. Confirm metadata and scope

Print a summary:

• Tags to be set: list all key-value pairs.
• Target files: count and confirm.
• Backup location: where _original sidecars will be stored.
• Confirm before proceeding.

4. Backup (if requested)

# exiftool creates _original sidecars by default, but also offer explicit backup
mkdir -p backup/
cp -r "<target>" backup/

5. Write metadata

Single file:

exiftool -Artist="Daniel Rosehill" -Copyright="© 2026 Daniel Rosehill" \
  -ImageDescription="Sample photo" "<file.jpg>"

Multiple tags at once:

exiftool \
  -Artist="<artist>" \
  -Copyright="<copyright>" \
  -ImageDescription="<desc>" \
  -Keywords="<key1>,<key2>" \
  "<file.jpg>"

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 -Artist="<artist>" -Copyright="<copyright>" {} \;

Append -overwrite_original to discard _original sidecars, but only if a backup was made in step 4.

6. Verify

Sample a few output files and confirm the metadata was written:

exiftool -Artist -Copyright -ImageDescription "<sample.jpg>"

If metadata did not stick (e.g., PNG text chunks), try the XMP-specific path:

exiftool -XMP:Artist="<artist>" -XMP:Copyright="<copyright>" "<file.png>"

7. Cleanup (optional)

If the user accepted -overwrite_original, remove _original sidecars:

find <target> -maxdepth <1|999> -type f -iname '*_original' -delete

Output / side effects

• Metadata tags written to original files (or to a copy if the user requested a separate output directory).
• _original sidecars created in the same directory as each file (unless -overwrite_original was used).
• Original files are modified (unless a backup was made in step 4).

Notes

• EXIF vs. IPTC vs. XMP: The same field (e.g., copyright) can live in EXIF, IPTC, and/or XMP. Some readers check only one format. exiftool intelligently maps to the appropriate group, but document which format was used:
  • EXIF: structured, camera/lens/exposure info. Limited size.
  • IPTC: editorial metadata (keywords, description, copyright). Limited size.
  • XMP: extensible, can hold arbitrary key-value pairs.
• PNG and HEIC: exiftool writes metadata to PNG as XMP in iTXt chunks. HEIC is complex; check the _original sidecar to ensure metadata persisted.
• Tag size limits: EXIF and IPTC have field-length limits. Very long descriptions (>500 chars) should go in XMP. exiftool warns if a value is too large.
• Permanent writes: Always create a backup before bulk metadata writes. Metadata corruption is rare but possible.
• Preserve other metadata: By default, exiftool -Tag=value file preserves all other metadata. Use -all= if you want to nuke everything before writing (not recommended).
• Depends: apt install libimage-exiftool-perl.