Williams-MBP:~ wmfs$ brew info libjpeg
jpeg: stable 9d (bottled)
Image manipulation library
https://www.ijg.org/
/usr/local/Cellar/jpeg/8d (19 files, 708.2KB) *
  Poured from bottle on 2020-06-19 at 10:50:07
/usr/local/Cellar/jpeg/9d (21 files, 751KB)
  Poured from bottle on 2020-06-19 at 10:28:04
From: https://github.com/Homebrew/homebrew-core/blob/master/Formula/jpeg.rb
==> Analytics
install: 157,018 (30 days), 537,391 (90 days), 1,811,716 (365 days)
install-on-request: 5,369 (30 days), 19,702 (90 days), 72,396 (365 days)
build-error: 0 (30 days)
Williams-MBP:~ wmfs$ brew switch libjpeg 9d
Cleaning /usr/local/Cellar/jpeg/9d
Cleaning /usr/local/Cellar/jpeg/8d
18 links created for /usr/local/Cellar/jpeg/9d