Performance:
- Files on external drives (SSD or HDD, APFS or exFAT) are now memory-mapped instead of being read in full before the preview appears. 4D files open up to 14× faster, and memory use stays low even for files of several hundred MB.
- Faster first preview of large files: MIQ now tells macOS in advance which parts of a file the preview needs, so they're read in large chunks instead of small pieces.
New:
- Thumbnails: a Skip large (compressed) files setting controls the size limit above which compressed MGH, MIF and NRRD files keep Finder's standard icon (default 100 MB).