A guide to photo timestamps and explicit timezone offsets

Three different date concepts

  • EXIF DateTimeOriginal: the camera’s recorded wall-clock capture time.
  • EXIF OffsetTimeOriginal: an optional UTC offset that makes the wall-clock time unambiguous.
  • Windows Created and Modified: filesystem timestamps shown by Windows and changed by copy, restore and edit operations.

Changing one does not automatically rewrite the others. Fix My Photo Library reads EXIF evidence for a preview but its date operation changes selected Windows timestamps on a new copy. It does not rewrite the original photo’s embedded EXIF.

Why timezone offsets matter

The string 2021:06:18 11:42:30 says what a camera clock displayed, but without an offset it does not say whether that was UTC, British Summer Time, or another local timezone. Converting it to UTC without context can shift a photo by hours.

No offset in the metadata? The app labels the time as needing a timezone decision. Embedded-date copy mode skips files without a valid explicit offset; alternatively, a user can choose an explicit offset and date rule for a batch.

Why make a corrected copy?

A copy-first workflow leaves the source image available for comparison. The app rechecks the source hash before copying, verifies the copy’s content, then sets the requested Windows Created and/or Modified dates. Existing names are not overwritten.

Advanced users can explicitly choose an in-place Windows timestamp change after a separate warning. The action journal records old/new timestamps and a hash; History offers Undo only while content and timestamp values still match. The tool never rewrites camera metadata.

Before you change dates

  1. Check which date the camera embedded and whether an offset is present.
  2. Compare against a trusted source such as an original export or contemporaneous record.
  3. Use a date with a clear timezone offset; do not assume the current Windows timezone matches an old trip.
  4. Review the destination and generated copy before reorganising or removing anything.

Checking image health too?

Read the broken-photo FAQ to understand supported codecs and what a failed decode can—and cannot—tell you.