Summary
Emails show as opened with Google Image Proxy IPs even when recipients haven't opened them because Google and other email clients use image proxies for security, privacy, and performance. These proxies pre-fetch images, triggering open tracking pixels automatically, regardless of actual user interaction. Factors such as Apple's Mail Privacy Protection (MPP), firewalls, anti-virus scanners, and email security solutions like Proofpoint (though Proofpoint doesn't directly interact with Google's Image Cache) also contribute by pre-loading or scanning images. Consequently, traditional open rates based on pixel tracking are increasingly unreliable, reflecting machine interactions rather than genuine human engagement.
Key findings
- Image Proxy Pre-fetching: Google Image Proxy and other services pre-fetch images for security, privacy, and performance reasons, leading to inflated open rates.
- Inaccurate Open Tracking: Traditional open tracking methods based on pixel tracking are increasingly inaccurate due to automated image loading by various services and security measures.
- Machine vs. Human Interaction: Open tracking pixels primarily capture machine interactions (e.g., proxy servers, security scans) rather than actual human engagement with the email.
- Impact of Privacy Measures: Privacy measures like Apple's Mail Privacy Protection (MPP) and advanced privacy settings in email clients further affect the reliability of open rates.
Key considerations
- Re-evaluate Open Rate Reliance: Marketers should re-evaluate their reliance on open rates as a primary metric due to the increasing unreliability caused by automated image loading.
- Focus on Engagement Metrics: Shift focus to more reliable engagement metrics such as click-through rates (CTR), conversions, website traffic, and other forms of direct interaction.
- Understand Proxy and Security Impact: Understand the impact of image proxies, security solutions, and privacy settings on email tracking and adjust strategies accordingly.
- Segment and Personalize: Focus on improved segmentation and personalization strategies to deliver more relevant content, aiming to increase genuine user engagement and make other metrics more valuable.
What email marketers say
10 marketer opinions
Emails are often reported as opened with a Google Image Proxy IP address even when the recipient hasn't opened them because Google Image Proxy pre-fetches images in emails for security, privacy, and performance reasons. This pre-fetching triggers open tracking pixels, leading to inflated or inaccurate open rates. Additionally, other factors like Apple's Mail Privacy Protection (MPP), firewalls, and security scanners also contribute to this phenomenon by automatically loading images, further distorting open rate metrics.
Key opinions
- Google Image Proxy: Google Image Proxy pre-fetches images for security, privacy, and performance, leading to inflated open rates.
- Inaccurate Open Rates: Open rates based on pixel tracking are becoming increasingly unreliable due to automated image loading by Google Image Proxy, Apple MPP, and other security measures.
- Machine Interactions: Open tracking pixels primarily capture machine interactions with email content rather than genuine human engagement.
- Other Services: Services such as Proofpoint, Apple MPP, firewalls and antivirus scanners impact open rates by pre-loading or scanning images, thus triggering open tracking.
Key considerations
- Rethink Open Rate Metrics: Email marketers should reconsider relying solely on open rates as a key performance indicator (KPI) due to their increasing inaccuracy.
- Focus on Engagement: Shift focus to more reliable engagement metrics such as click-through rates (CTR), conversions, and website traffic to gauge campaign success.
- Segment and Personalize: Improve segmentation and personalization strategies to deliver relevant content that encourages genuine interaction, making engagement metrics more meaningful.
- Monitor Deliverability: Closely monitor email deliverability and sender reputation to ensure messages reach the inbox, which is fundamental for any metric to be relevant.
Marketer view
Email marketer from MarketingProfs discusses that Google Image Proxy is one of several factors (including Apple MPP) contributing to the unreliability of email open rates. These services pre-load images, making open rates an inaccurate metric.
13 Jun 2024 - MarketingProfs
Marketer view
Email marketer from StackOverflow discusses how Google Image Proxy and other email clients load images for security and caching, leading to inflated open rates. There is no reliable way to differentiate between human opens and proxy-triggered opens using pixel tracking alone.
25 Apr 2025 - StackOverflow
What the experts say
3 expert opinions
Emails are registering as opened with Google Image Proxy IPs even when recipients haven't opened them due to Google and other services using image proxies for security and caching. These proxies fetch images automatically, triggering open tracking pixels, resulting in inflated open rates. Proofpoint, while offering email security, operates separately from Google's Image Proxy and does not directly interact with or load images into the Google Image Cache.
Key opinions
- Image Proxy Influence: Image proxy services like Google's fetch images for security and pre-caching, inflating open rates.
- No Proofpoint Interaction: Proofpoint does not interact with Google's Image Cache, operating as a separate security layer.
- Automatic Image Loading: Image proxies load images automatically, triggering open tracking pixels even if the recipient doesn't view the email.
Key considerations
- Re-evaluate Open Rates: Open rates may not accurately reflect user engagement due to automatic image loading by proxies.
- Focus on True Engagement: Focus on other metrics that indicate true user engagement (e.g., click-through rates, conversions).
- Understand Security Impact: Consider the impact of security services like Proofpoint and image proxies on email tracking.
Expert view
Expert from Spam Resource explains that image proxy services like Google's fetch images in emails for various reasons, including security and pre-caching. This can lead to inflated open rates because the open is recorded when the proxy fetches the image, not when the user opens the email.
15 Jun 2025 - Spam Resource
Expert view
Expert from Word to the Wise shares that image proxy usage by email clients and security solutions result in opens being reported, despite recipients not actually viewing the email. This happens because the proxy loads the images, triggering open tracking pixels.
5 Jul 2021 - Word to the Wise
What the documentation says
3 technical articles
Emails are showing as opened with Google Image Proxy IPs even when recipients haven't opened them primarily because Google uses image proxies for enhanced security and improved user experience by pre-fetching images. This pre-fetching triggers 'open' notifications, regardless of actual user interaction. Litmus highlights that these image caching techniques, along with broader privacy changes, negatively impact the accuracy of open rates. Microsoft's documentation further underscores this issue by explaining privacy settings in Outlook that prevent automatic image loading, impacting open tracking until user permission is granted.
Key findings
- Google Image Proxy: Google uses image proxy to improve security and user experience, leading to inflated open rates.
- Impact of Privacy Changes: Privacy changes, including image caching, affect the accuracy of open rates, making it difficult to measure genuine engagement.
- Privacy Settings: Privacy settings in email clients like Outlook can prevent automatic image loading, further impacting open tracking.
Key considerations
- Reassess Open Rate Metrics: Marketers should reassess their reliance on open rates as a primary metric due to privacy changes and image proxy pre-fetching.
- Focus on Alternative Metrics: Prioritize alternative engagement metrics like click-through rates, conversions, and website traffic to gauge campaign performance.
- Optimize for Privacy: Optimize email campaigns with privacy in mind, acknowledging that open rates may be suppressed due to user settings and image proxy behavior.
Technical article
Documentation from Google Workspace Admin Help explains that Google uses image proxy for security and to improve user experience. This proxy fetches images on behalf of the user, which can trigger an 'open' notification even if the user hasn't viewed the email directly.
23 Mar 2025 - Google Workspace Admin Help
Technical article
Documentation from Litmus outlines the impact of privacy changes, including Google's image caching, on email open rates. Google's pre-fetching of images can falsely trigger opens, making it difficult to accurately measure genuine engagement.
5 May 2022 - Litmus
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