When a company sends an email newsletter to customers, certain email clients (Gmail, Outlook) display a short snippet of preview text in the recipients inbox before the customer opens the email. As I understand it, there are two techniques to control what preview text appears regardless of the visible design and content of the email:
1) start the email with an invisible 1x1 pixel that uses the desired preview text as alt text
2) create a div in the html template with "display:none"
Which option is best in terms of computability with all major email clients?