You can't, unless the recipient's email client displays images. Most do not do this by default. If the user chooses to display images, you can include a link

You can't, unless the recipient's email client displays images. Most do not do this by default. If the user chooses to display images, you can include a link to a 1x1 image in the email, and then monitor your server logs to see who opens it. There are plenty of software packages that do this. More information here: http://stackoverflow.com/questions/973143/tracking-email-bounces-opens-clicks http://stackoverflow.com/questions/973143/tracking-email-bou...