Show large icons or small icons for mailboxes in Mac Mail

The main Mac Mail window includes a side pane on the left which contains the default and custom mailboxes (email folders) you have created, as well as to-do tasks and reminders, plus any RSS feeds to which you subscribe in Mail (in addition to remote mailboxes, which you'll see appear if you subscribe to MobileMe, for example). The size of these mailboxes and icons on the left can be customized with a couple of clicks, as you'll learn in this tutorial - this can be quite useful when you are either using a large screen resolution (everything looks "small" on your display), or when your vision isn't what it used to be; conversely, if you are using a small screen resolution (everything looks "large" on your display), you can reduce the size of these icons and make them smaller - literally with two targeted clicks.

Make Mac Mail icons larger or smaller

• When you are inside the main Apple Mail window, look at its bottom left corner (at the bottom of the side pane), and you will see three buttons.
• Click on the "gear" icon, and a submenu will appear:
  
  
• The second menu item from the bottom reads "Use Small Mailbox Icons", and either displays a checkmark on the left, or not: the screenshot above shows you that menu when we are using large icons. As soon as we click this option, Mac Mail will show a checkmark on the left of this setting, and switch to using small icons.
• Note that this setting is "persistent": Apple Mail will remember it between sessions, no need to change the size of your icons every time, and that it is immediate - no need to restart your email program to see the change take effect.

And that's all you need to do to change the size of mailbox icons in Mac Mail; a later tutorial will explain how to customize the main toolbar itself (on top of the Mail window).