Add srcset to Single Product gallery thumbnail images

[Aljullu]

Changes proposed in this Pull Request:

Fixes #48431.

This PR adds a srcset attribute to thumbnail images displayed in the Single Product page for products that have multiple images or variable products with different images for each variation.

How to test the changes in this Pull Request:

1. Create a product with several images.
2. Visit the product in the frontend.
3. Verify the thumbnail images aren't blurred. If you aren't sure, you can open your browser devtools (F12), inspect the image and verify it has a srcset attribute.

Before	After

(Note: you might to open the PRs in a new tab to see the difference)

Changelog entry

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Changelog Entry Details

Significance

• Patch
• Minor
• Major

Type

• Fix - Fixes an existing bug
• Add - Adds functionality
• Update - Update existing functionality
• Dev - Development related task
• Tweak - A minor adjustment to the codebase
• Performance - Address performance issues
• Enhancement - Improvement to existing functionality

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Changelog Entry Comment

Comment

[github-actions]

Test using WordPress Playground

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Test this pull request with WordPress Playground.

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[github-actions]

Size Change: 0 B

Total Size: 2.5 MB

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[github-actions]

Hi @WunderBart,

Apart from reviewing the code changes, please make sure to review the testing instructions as well.

You can follow this guide to find out what good testing instructions should look like:
https://github.com/woocommerce/woocommerce/wiki/Writing-high-quality-testing-instructions

[WunderBart]

Tested locally, product thumbnails have the srcset attribute and they always stay sharp. Nice improvement, thanks! 🚀