Email clicks higher than email opens on report
I'm a little confused about a few reports I pulled in Marketo. I created 2 Smart Lists - one to show exactly who clicked on a link in the email, and another to show who opened the email. Some of the leads on the click report do not show up on the open report. Any idea how this is possible? Also, what is considered to be a true open in Outlook? I heard that you have to click download pictures in order for it to register as an open, however this email has no images. If it has no images, do you have to double-click on the email in your Outlook inbox to have it register as an open?