pub fn extract_largest_preview(path: &Path) -> Result<Option<Vec<u8>>, String>Expand description
Bytes of the largest embedded JPEG in this TIFF-based RAW, or
None if the file doesn’t contain a recognisable embedded preview.
Returns Err only for I/O failures and malformed TIFF headers —
“no preview found” is the Ok(None) case and is normal for some
older / minimal RAWs. Callers should surface that as “couldn’t
decode this photo” rather than a hard error.