2021-11-17_12.09.20-1.jpeg Apr 2026

: The timestamp ( HH.MM.SS ) showing when the image was captured or saved (12:09 PM and 20 seconds). Periods are used here because colons are invalid characters in Windows filenames.

: The date in YYYY-MM-DD format (November 17, 2021). This ISO 8601-style format is the gold standard for automatic chronological sorting . 2021-11-17_12.09.20-1.jpeg

This format is common for automated exports (like Google Photos or Android device backups) to ensure files remain unique and sortable. : The timestamp ( HH

What is your favorite date and time format in a file name? [closed] 2021-11-17_12.09.20-1.jpeg