Many document formats store metadata with their data. Choosing the right ones to use must ensure their access, indexing and search. Here’s how to check those, and why Keywords are usually a good choice.
EXIF
If generating QuickLook thumbnails and previews, and indexing metadata for Spotlight, depend on UTIs, how come they tolerate misleading file extensions? A simple practical demo.
Information about the data in a file can be found in different places: in the file’s attributes, in extended attributes that tend to be Mac-only, and embedded with the data, as in EXIF.
Why are some file metadata embedded in their main data, and others stored separately as extended attributes? How can I tell them apart?
Where to look for file metadata in the Finder, and how you can customise it, in spite of its apparent confusion. And how APFS takes care of extended attributes for you.
Never underestimate the time and effort involved to enter data for old photos when you scan them in.
Why does mdls not give full image metadata?
The Eclectic Light Company 