friends-of-hyva / magento2-preload-images

friends-of-hyva/magento2-preload-images

Preload images above the fold to improve performance metrics.

  • Vinai Kopp
magento2-module Compatibility: 2.4.7-2.4.9 Code Quality: Warning Tests: N/A Security: Pass BSD-3-Clause

Preload Images via HTTP Link response header

This module was built as an experiment during the MageUnConf Hackathon in Cologne, in September 2022.

The goal is to improve the user experience by loading images that are guaranteed to be displayed above the fold earlier.
The idea came out of interesting discussions with Tsvetan Stoychev and his experience working at Akamai on the frontend performance team.

Installation

Run the command

composer require friends-of-hyva/magento2-preload-images

Usage:

Import the Hyva\PreloadImages\ViewModel\PreloadImages view model into your template and call the add() method, passing the image URL string as a parameter.

In Hyvä the ViewModelRegistry can be used, with Luma based themes the view model has to be passed into the template as a block argument using Layout XML.

Hyvä Example:

/** @var string $imageUrl */
$viewModels->require($viewModels->require(PreloadImages::lass)->add($mainImageData);::class)->add($imageUrl);

Details

The preloading is triggered in the browser by a Link header.

Take this screenshot of a PDP waterfall chart on slow 3G without preloading:
[image: Load times waterfall chart of a PDP without preloading]

You can see the main product image wp13-orange_maim_1.jpg begins loading shortly after the protia-capri.html document is received.
The browser requests the main product image after the css files used by the page.

Here is the screenshot of the same page with preloading:
[image: Load times waterfall chart of a PDP with preloading]
With preloading, the browser requests the main product image before even the css files.

Be aware!

The feature this module provides is well in the range of micro-optimization, and if used without care can harm a websites SEO metrics.
If preloading an image improves the customer experience or a search engine ranking metric really depends on the site in question and the customer usage base.

Also, it will require a relatively high amount of visitors and careful monitoring to determine if it improves the situation for the majority of visitors.

License

Copyright 2022 Vinai Kopp & Hyvä Themes BV

The module is released under the BSD-3 Clause license.

No changelog yet

The vendor hasn't published a changelog. Tagged releases appear in the Versions tab.

Versions
Version Stability QA Status Compatibility Released
1.0.0 stable Pass Magento 2.4.7-2.4.9 Details 2022-10-03 13:54:40

No dependencies declared

This package's composer.json doesn't declare any required, suggested, replaced, or conflicting packages.

Compatibility

Each Magento release line is installed on its supported PHP versions, then the module is built (DI compilation + static-content deploy) and its unit and integration suites are run. The matrix shows the lines and PHP versions the module is confirmed to install and run on. Code-quality results further down (phpstan, phpcs, …) are reported separately and never affect compatibility.

Compatibility matrix (Magento × PHP)
Magento PHP 8.2 PHP 8.3 PHP 8.4 PHP 8.5
2.4.7 Pass Pass
2.4.8 Pass Pass
2.4.9 Pass Pass

Code Quality

Advisory checks against the module's source. Static analysis runs once across the whole module; PHPStan re-runs per Magento + PHP version because resolvable symbols differ between releases. These NEVER affect the Compatibility badge — a phpcs finding can't make a module incompatible.

Static analysis

Coding standards (phpcs), mess detection (phpmd), copy-pasted code (cpd), PHP cross-version compatibility, composer.json validity. Each runs once for the whole module.

Static analysis results
Tool Status Findings Summary
PHPCS Warning 1 1 warning (ruleset: Magento2)
PHPMD Warning 1 1 rule violation (UnusedPrivateMethod:1)
Cpd Pass 0
Composer validate Pass 0

PHPStan

Type-checks the module's PHP against a real Magento install at the configured gate level. Re-runs per Magento and PHP version because resolvable symbols differ between releases. Cell → details modal.

PHPStan results by Magento and PHP version
Magento PHP 8.2 PHP 8.3 PHP 8.4 PHP 8.5
2.4.7 Pass Pass
2.4.8 Pass Pass
2.4.9 Pass Pass

Tests

Unit and integration suites, run for each applicable Magento and PHP version. A test failure speaks to the module's behaviour, not its compatibility with a Magento line, so it is reported here separately and never reddens the compatibility matrix.

Unit tests

Unit tests results by Magento and PHP version
Magento PHP 8.2 PHP 8.3 PHP 8.4 PHP 8.5
2.4.7 N/A N/A
2.4.8 N/A N/A
2.4.9 N/A N/A

Integration tests

Integration tests results by Magento and PHP version
Magento PHP 8.2 PHP 8.3 PHP 8.4 PHP 8.5
2.4.7 N/A N/A
2.4.8 N/A N/A
2.4.9 N/A N/A

Security

Security checks run directly against the module: an audit of its declared dependencies for known vulnerabilities (composer audit) and a scan of its source for malware and web-shell signatures. Each runs once. A malware detection fails the version outright.

Security results
Tool Status Findings Summary
Composer audit Pass 0
Malware scan Pass 0
License
BSD-3-Clause
Authors
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