You can configure Mailtrack so that it doesn't track by default every email you send.
To do so:
1) Go to the Account and Settings section in your dashboard.
2) Click Settings and uncheck the Track emails by default option.
3) Click Save changes.
You can also disable the tracking on a per email basis.To do so:
1) Click on the tracking button in the Gmail compose window.
2) Deselect the option Enable tracking for this email.
3) Send the email.