There are lots of potential ways to track via an email besides images. I'm not sure which work in Gmail. But the more common marketer's strategy is just to prov

There are lots of potential ways to track via an email besides images. I'm not sure which work in Gmail. But the more common marketer's strategy is just to provide a lead and a hyperlink - let the user click it and track them in their browser. Marketers can still embed images with unique URIs that identify an address and know when a user opens it. Even if Google caches it, they know that address opened it once (because Google doesn't preload images until the user opens the mail)