What the items in the OS X Storage Summary mean
Article written by Best Businesses
The storage within the more info tab of about this Mac gives a breakdown of your storage of the Mac. This storage summary will give your total free disk space and six categories on how your disk storage is used.
Audio – This covers all music and audio files stored on the Mac, including the iTunes Song and Music libraries. Apple Music offline downloads are also included here.
Movies – all movie files, whether user created from iMovie or downloaded from iTunes on online. I order to be classified as a movie file, it cannot be in an archive.
Photos – all picture documents stored locally, including user imported photos from an iPhone or Camera, screen shots, or digitally created image files from any image software. Cached image from Photos also fall here.
Apps – all applications and executable files, including the /Applications directory and any other .app files stored around the Mac. This will include older files if the removal process didn’t complete delete all the files within the subdirectory from Applications.
Backups – all locally stored backup files from Time Machine or iPhone (this is often zero KB if you turned the feature off)
Other – every other document and file type on the Mac, including archives, zip files, docs, txt, pdf. If it does not fall into any of the previous categories, there is where it will end up.
Free space – This is the freely available space shown in relation to used capacity.