The basic concept is that you're placing an image request in the body of the email. If you're able to load an external image into the email itself, use a hardcoded image request as the source with the variables you want as query string parameters.
Alternatively, Adobe Campaign has the capability to track email opens as well.
let me confirm that for you. Could you also give me some more detail meanwhile, are you adding a campaign link to your email which leads to a landing page in your site? If yes, a good way would be to add a campaign code to your links and then you can track url parameters in analytics. Thanks!