Google's move to start displaying email images by default in Gmail is going to help marketers, in part, to more accurately track how many people open their emails.
Gmail will start serving images through its proxy servers rather than serve images directly from their external hosts, Google announced Thursday. This allows Google to check the images for viruses and malware before an image is showed in Gmail. This extra step means that it is now secure enough to let Gmail users see images displayed in desktop browsers and in mobile devices running iOS and Android, it said.
Before Gmail users had to click the "display images below" link to see them.
Allowing images by default lets marketers better track how many people open their emails. Many email service providers that send bulk email on behalf of clients use a tiny, single pixel sized image in each email, Matthew Grove of MailChimp said in a blog post.
When someone views the images in an email with a tracking pixel MailChimp's image hosting servers gets a request for the tiny image to load, and that request is used to track how many unique persons opened the email and how often they opened it, Grove said.
Google's decision to start caching the images on its servers lowers email marketers' ability to track repeat opens, Grove said, but turning those images on means, in theory, unique opens can be tracked more accurately.
"That's exciting in a nerdy data way," he said.
It would indeed increase overall accuracy of "emails read," said Kimon Zorbas, vice president of IAB Europe, in an email. Before there were probably users who read the emails without downloading the associated pictures, he said. "Now, Gmail will always download the picture, so you capture those users you didn't before."
Google said that in some cases, senders may be able to know whether an individual has opened a message with unique image links. However, if Gmail considers a sender or message potentially suspicious, images won't be displayed and people will be asked if they want to see the images, it added.
Senders can't use image loading to get information like an IP address or location, nor can they use it to set or read cookies in a browser, according to Google. That might be a disadvantage when companies want to know the devices or browsers people use to read the emails and also hides locations based on IP addresses.
Gmail users can still decide to view an email's images on a message-by-message basis by checking the option "ask before displaying external images" under the general tab in settings, Google said. This option will also still be the default for users who previously selected "ask before displaying external content", it added
Loek is Amsterdam Correspondent and covers online privacy, intellectual property, open-source and online payment issues for the IDG News Service. Follow him on Twitter at @loekessers or email tips and comments to email@example.com