In OS X the view options for a specific window instance are inherited from the first opened folder, which usually is the user's home folder. This means that if you have the home folder in a ...

Apple's Preview application can open entire folders of images, but this feature should be used cautiously.

Instead, folders show a pair of dashes (--) in the Size column. macOS skips calculating folder sizes by default to keep List view performance fast, especially in directories with many nested files.

How to view the size of folders within the Finder’s list view Step 1: Open Finder Step 2: In the menu bar select View → as List Step 3: In the menu bar, select View → Show View Options ...