It is obvious that many people try to track their sent emails by using online tools which embed an invisible external image to the email's body.

The workaround which most people are familiar with is to block external images. But that's actually not a good approach and maybe there is an important image in that email which we want to see.

I think the best solution would be to tell Gmail to download external images (or maybe just a resized tiny version of them) to its servers and we get them from Gmail's servers.

Does anybody know that if doing something similar to this is possible using Gmail?

  • 2
    All images are already served via Google's servers (a relatively recent security feature that blocks "malicious" images), however, this does not necessarily prevent the original sender from tracking the email (at least determining whether it's been read or not) since the original image needs to be requested at some point (by Google). Unfortunately, when Google implemented this feature they also changed the default setting to always show images.
    – MrWhite
    Nov 9, 2014 at 17:31

1 Answer 1


Gmail has been doing this since December, 2013.

From the official Gmail blog

Have you ever wondered why Gmail asks you before showing images in emails? We did this to protect you from unknown senders who might try to use images to compromise the security of your computer or mobile device.

But thanks to new improvements in how Gmail handles images, you’ll soon see all images displayed in your messages automatically across desktop, iOS and Android. Instead of serving images directly from their original external host servers, Gmail will now serve all images through Google’s own secure proxy servers.

So what does this mean for you? Simple: your messages are more safe and secure, your images are checked for known viruses or malware, and you’ll never have to press that pesky “display images below” link again. With this new change, your email will now be safer, faster and more beautiful than ever.

As mentioned by w3d this does mean that the original host of the image will know when Google retrieves the image to cache it, but that doesn't necessarily mean that it's been seen by a human, so the whole idea of web bugs is now quite unreliable.

For an added measure of protection, you can put your Gmail settings back so that images aren't shown until you expressly download them. (They'll still be from Google's cache, though.) That's "Ask before displaying external images" under the General tab in Settings.

  • Well if Gmail always try to cache external images through its proxy server as soon as new emails are received, then the sender will not be aware if we have opened the email, Because Gmail always fetches images and the hits on email tracker web server will not have any meaning for the tracker.
    – Aliweb
    Nov 11, 2014 at 14:05
  • @ali ...and spammers will be able to detect that emails are being received. However, I kind of have my doubts whether Gmail always fetches images and perhaps only fetches them as required. It would seem to place unnecessary load on Google if Gmail fetched all images in all emails as they pass through its servers? And Google does state in the documentation: "...senders may be able to know whether an individual has opened a message with unique image links." - this statement would be incorrect if Google always fetched images.
    – MrWhite
    Nov 11, 2014 at 17:03

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