WS-NA: Bumps Billboard image max srcsize to from 660px to 800px

[Isabella-Mitchell]

Resolves JIRA: WS-NA (Stretch task of https://bbc.atlassian.net/browse/WS-2615 - will make a separate ticket if it needs one)

Alternative (simpler but less effective approach) to #14255

(Picked 800px since this is the max srcSet size provided for promo images used in Homepage curations).

Summary

Updates the Billboard component’s image rendering to request a larger maximum image width so the generated srcset includes an 800w candidate, improving image quality options for high-prominence billboards.

Noted that PS use 960px here: https://www.bbc.co.uk/news/bbcindepth (they are also using a PNG.webp and not jpeg.wepb - if that makes a difference).

Code changes

• Increased Billboard image originalImageWidth from 660 to 800 so createSrcsets includes an 800w entry.
• Added a unit test asserting the rendered image srcset includes 800w for the high-prominence variant.

Testing

Use storybook or compare test asset, e.g. http://localhost:7081/kyrgyz?renderer_env=test and https://www.test.bbc.com/kyrgyz
See image is a teeny bit less blurry - can see 800px is the largest size in the srcSet

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[Copilot]

Pull request overview

Updates the Billboard component’s image rendering to request a larger maximum image width so the generated srcset includes an 800w candidate, improving image quality options for high-prominence billboards.

Changes:

• Increased Billboard image originalImageWidth from 660 to 800 so createSrcsets includes an 800w entry.
• Added a unit test asserting the rendered image srcset includes 800w for the high-prominence variant.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated no comments.

File	Description
src/app/components/Billboard/index.tsx	Increases the maximum image width used for srcset generation to include 800w.
src/app/components/Billboard/index.test.tsx	Adds coverage to confirm 800w appears in the rendered srcset for high prominence.