@corey34 - The tracking pixel is inserted by "CampaignHelper:arseContent" ( /apps/common/components/helpers/CampaignHelper.php )and it is looking for the closing </body> tag and adds the img tag right before it.
Where i can add in last line , like if i want to add pixel https://mydomain/impression/something-to-track-to-open/ ?if ($appendBeacon && !empty($subscriber->subscriber_id) && !self::contentHasOpenTrackingBeacon($content, $campaign, $subscriber)) {
$beaconImage = self::getOpenTrackingBeacon($campaign, $subscriber);
$content = str_ireplace('</body>', $beaconImage . "\n" . '</body>', $content);