Messages:
Display TEXT mails instead of HTML when available: By default, Mail displays the new messages in RTF or HTML format. You can use this option to display them in Text format, without style and without attachment preview. This speeds up the display. To see the attachments, click the Save button located in the header of the message.
Turn on display attachments in messages: By default, some attachments, including images, are visible directly in the message body. You can use this option to view or not these attachments in messages.
Minimum font size: By default, Mail's messages appear with a minimum font size of 10. You can use this option to increase or decrease this size.