Sometimes, when building a diagnostic OS, you need to optimize for space – you might be trying to fit the OS onto a small USB flash drive, or you want to decrease NetBoot times.

Once you’ve thrown away the obvious culprits – thanks to something like GrandPerspective – you might decide to trash the contents of /System/Library/Compositions/. I did. Unfortunately, this will break Photo Booth.

We relied on Photo Booth to test the iSight camera, so I came up with an alternative. Save this script as an application and put it in the Dock. Heck, I gave it the Photo Booth icon. It opens a new “movie recording” window in QuickTime Player, but it’s not actually recording. Good for a quick test, and faster than Photo Booth.

Tested with: 10.7, 10.8, 10.9, 10.10