View messages based on size.
If your goal is to reduce the overall size of your mailbox or of a specific folder in your mailbox, one strategy is to read, and then respond to, file, or delete messages based on their sizes. To achieve this goal, you can use tools in Outlook to monitor individual message sizes. Staying aware of sizes (and knowing what your organization's size limits are) will also ensure that your messages are properly delivered or received.
As you look at messages in your Inbox (or in any other folder that stores e-mail messages), you can group messages by size.
If you point to Arrange By on the View menu, and click Size, your messages will be sorted into groups such as Tiny (< 10 KB), Small (10 - 25 KB), and so on. Make sure Show in Groups (also on the Arrange By submenu) is selected.