Smush's compressed image files are just static assets by the time a crawl captures them, and its optional CDN add-on rewrites image URLs the same way — both served static with high confidence. WebP/AVIF delivery is the exception: Smush typically decides whether to serve the modern format using a server-level rewrite rule or a PHP-side check of the browser's Accept header, a per-request decision a plain static host doesn't make on its own.
The risk here isn't broken pages, it's invisible ones: a visitor silently gets the original, larger image format instead of WebP/AVIF, and nothing about the page looks wrong — it's just slower than it should be.
Hybrid
Compressed image files, and CDN-rewritten image URLs when Smush's CDN add-on is enabled, are both served from the static release as-is.
WebP/AVIF format selection depends on a live per-request check (a server rewrite rule or a PHP Accept-header check) that a static host doesn't run unless it's separately configured at the host or CDN layer.
None needed — Smush declares no public routes of its own. WebP/AVIF delivery isn't something a bridge route can fix; it needs to be replicated at the host or CDN layer instead.
No special setup — detected automatically once active. If WebP/AVIF savings matter, confirm the format is still actually being served once the site goes static.
This is the one caveat worth taking seriously: without that content-negotiation rule replicated at the host or CDN layer, every visitor silently gets the original, larger image format instead of WebP/AVIF — not a broken page, just a quiet performance regression that's easy to miss. Pre-generated <picture>/srcset markup sidesteps the problem entirely if the savings matter for this site. None of this has been behaviorally validated against a live install — the classification is rule-derived, which is why WebP/AVIF confidence is capped lower than plain compression.
Static Shield Lite is free to install and inspects your actual plugins, not just what's publicly visible.
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