Published on 2025-06-26T05:35:47Z

What is an Image Beacon in Analytics? Examples with PlaSignal and GA4

An Image Beacon is a tracking technique in analytics that uses a tiny, usually invisible 1×1 pixel file to collect and send data when a web page or email is loaded. Instead of running full JavaScript tags, browsers request this pixel as an image from an analytics server, carrying metadata (such as page URL, timestamp, and browser details) in its query parameters. This lightweight method is often used for environments where JavaScript is disabled, in email tracking, or for privacy-forward analytics solutions like PlaSignal that operate without cookies. Although simple, image beacons excel at capturing basic pageview events and can be integrated with modern platforms like Google Analytics 4 via the Measurement Protocol.

Illustration of Image beacon
Illustration of Image beacon

Image beacon

A 1×1 pixel tracking beacon that sends pageview data via an image request without using cookies or JavaScript tags.

How Image Beacons Work

Image beacons rely on the browser’s ability to fetch images. When a 1×1 transparent pixel is embedded in a page, loading it triggers an HTTP GET request. Analytics servers decode query string parameters added to the image URL, extracting details like page path, referrer, user agent, and custom dimensions. This process occurs without executing any JavaScript on the client.

  • Embedding the pixel

    The pixel can be placed directly via an HTML <img> tag or injected through a minimal script. It’s typically styled to be invisible (height and width set to 1px or hidden via CSS).

  • Data transmission

    All relevant tracking data is encoded in the URL’s query parameters and sent with the image request.

    • Query string parameters:

      Key-value pairs appended to the image URL represent event data (e.g., page=/home, campaign=spring_sale).

    • Server processing:

      Upon receiving the request, the analytics backend parses the URL, extracts parameters, and logs the event in reports.

PlaSignal Implementation

PlaSignal offers a privacy-first, cookie-free analytics solution that uses image beacons under the hood to record pageviews.

  • Setup and preconnect

    Include a preconnect link to the PlaSignal endpoint to optimize DNS resolution before the beacon fires.

  • Tracking script

    Add the PlaSignal script tag which dynamically injects the 1×1 pixel beacon with your site ID and domain.

    • Code example: 
      <link rel="preconnect" href="//eu.plainsignal.com/" crossorigin />
<script defer data-do="yourwebsitedomain.com" data-id="0GQV1xmtzQQ" data-api="//eu.plainsignal.com" src="//cdn.plainsignal.com/PlainSignal-min.js"></script>

Google Analytics 4 (GA4) Example

Although GA4 primarily uses JavaScript tags, you can fall back to an image beacon via the Measurement Protocol for basic pageview tracking when scripts are blocked.

  • Measurement protocol setup

    Generate an api_secret in GA4 and obtain your measurement_id. These parameters authenticate and identify the data you send.

  • Image beacon fallback

    Embed an image tag pointing to the GA4 endpoint with required query parameters.

    • Code example: 
      <img src="https://www.google-analytics.com/mp/collect?measurement_id=G-XXXXXX&api_secret=YYYY&client_id=12345.67890&events=page_view" alt="" width="1" height="1" />

Advantages

Image beacons offer a streamlined way to capture pageviews without relying on client-side JavaScript or cookies, making them ideal for simple, privacy-conscious analytics.

  • Privacy-friendly

    Operates without third-party cookies, reducing fingerprinting and complying with strict privacy regulations.

  • Simple integration

    Easy to embed in static sites or email templates with minimal code.

Limitations

While effective for basic pageview tracking, image beacons cannot capture complex user interactions and can be affected by browser caching or privacy blockers.

  • Limited interaction data

    Cannot track scroll depth, clicks, or form submissions without additional scripts.

  • Potential blocking

    Ad blockers or strict privacy settings may prevent the image request, leading to undercounting.

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