To see more information about your messages, you may need to hide or resize the panes in Outlook.
If you're interested in size beyond the range of "Tiny," "Small," and so on, you can manipulate the Outlook window so that you can see the exact size for each message that lands in your Inbox.
Because most of the built-in views include the Size field by default, all you need to do to see size is to make more room in the list of messages. For example, if you hide the Navigation Pane and resize or temporarily close the Reading Pane, you'll be able to see more information about the messages in the list, including their sizes.
