GMail Image Caching - Better for Security, Worse for Marketing

What Does the New GMail Image Caching Update Mean for Email Marketing? 

Direct from Google:

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.

http://gmailblog.blogspot.com/2013/12/images-now-showing.html

How Images Were Used for Email Marketing

Images have served a very important function in email marketing. Images are used to track email opens and engagement while providing marketers with valuable data about when, where, and how their campaigns are being read.

Email tracking relies on a unique image being included in a campaign and that image being downloaded and displayed within the email. Every time the image is downloaded from the server, the tracking software marks that as an email open. Combined with things like click tracking and site analytics, open tracking via images helps give marketers a comprehensive view of how people are interacting with their campaigns.

To count opens reliably, software tools need those images to be downloaded every time someone opens an email. Gmail has started caching images for users accessing Gmail via the web interface: images are viewed only once on the original server while successive views will originate from the cached image on Google’s proxy servers.

What This Means for Marketers' Analytics and Users' Privacy

The main problem for marketers is that the unique downloads that tracking software looks for will no longer occur. Analytics tools will only see the initial download by Google and won’t record subsequent opens regardless of how many times a reader opens that email.

Some marketers also use geolocation to personalize email messages. They look at where the image is downloaded and feed users dynamic content based on their location. With Gmail’s new image caching behavior, geolocation could effectively break. Instead of being able to see where a reader is located, these services will see where Google’s proxy server is located—resulting in dynamic content tailored to the proxy server’s location.

On the flip side, now all spammers have a way of validating your address, since only images sent to valid Gmail addresses will be accessed.

As mentioned previously, marketers can send out an email with unique image names (easily done from their CDN or wherever) and when that image is loaded they'll know that that particular person opened it. Thus, the email was viewed. They can use this for test-and-target or AB testing on subject names, and also modify the images to lead to higher clickthroughs.

The proxying is only a privacy enhancement for people who already loaded images by default, and is actually a net loss in privacy for users who never loaded images. Now everyone will load images by default, and privacy-aware users will have to take action to gain that privacy back.In all cases the marketers won't get your IP and useragent - good or bad depending on perspective.


Hope this article cleared a few things up.