Basically, we can define an opener as a recipient who has opened your email. In tracking reality, and due to technical constraints, it’s slightly more subtle than that.

It should be noted that downloading images from your email will trigger the counting of an opening. This is the only possible solution, used by all tracking systems available on the market.

For this, just before sending, OxiMailing adds at the bottom of the message a transparent image one pixel high by one pixel wide (therefore completely invisible). This image is hosted on one of our servers.

With some email clients, web images are downloaded automatically as soon as an email is viewed, leading to a natural counting of the opening.

But for security reasons, some email tools (such as Microsoft Outlook) and Webmail (Gmail, Yahoo…) are configured to prevent automatic downloading of images, and user intervention is required for this download to occur.

Hence the interest in inserting at least one image hosted on the web in your message, in order to encourage the recipient to download the images.

👉 To simplify: if you only insert local images (present on your machine, therefore “embedded” in the email), the recipient who reads their emails with Outlook will not feel the need to download the images, since the email is already perfectly readable as is. And in this case, the small invisible image (which is hosted on the web) will not be loaded… and the opening will therefore not be counted!

In your opinion, why are prospecting emails from the largest companies composed of hosted images? Simply to obtain the most accurate opening rate possible!

All this to say that depending on how the message is designed, the opening rate reported in the tracking report may be underestimated compared to reality.

✅ Conclusion: here is another good reason to prefer web images to local images! To learn more about inserting web images: In a message, how to add an image?