If a recipient has disabled images in their email client, there is no way for Yesware to know if that recipient opened your email, so you won't receive any notifications of opens from that recipient.
In addition, to minimize the number of irrelevant tracking events that receive notifications, you can set your Yesware preferences to turn off "sender opens". This eliminates notification whenever you or anyone sharing your internet connection (e.g. colleagues on an office network) opens your tracked email. You can always see all message opens (including "sender opens") by viewing your personal Tracking Report.
When you send an email to several people, CC someone on an email, or if the message gets forwarded then we can only tell you that ‘somebody’ opened your message. But even still our customers tell us it’s fascinating to see when ‘somebody’ has opened a message several times because that either means they love the email or its being forwarded throughout the organization.