Is extend_cache_images enabled by default?

Yes. extend_cache_images is in CoreFilters, the default RewriteLevel, so it runs unless you turn it off with DisableFilters.

How do I turn off extend_cache_images?

Add ModPagespeedDisableFilters extend_cache_images on Apache or pagespeed DisableFilters extend_cache_images; on nginx. On IIS, add pagespeed DisableFilters extend_cache_images to pagespeed.config.

filter · Image filters

Extend cache for images (extend_cache_images)

Q: What does the extend_cache_images filter do?

Core filter, one of the three members of extend_cache. Rewrites image URLs to content-hashed .pagespeed.ce. URLs served with a one-year Cache-Control max-age, so browsers keep images for a year while a changed image gets a new URL. Use it when the origin cannot set long cache lifetimes itself; under CoreFilters it is already on through extend_cache, and rewrite_images produces content-hashed URLs of its own for every image it rewrites.

Category:: Image
CoreFilters:: Yes
OptimizeForBandwidth:: No
Risk:: Generally safe

Core filter, one of the three members of extend_cache. Rewrites image URLs to content-hashed .pagespeed.ce. URLs served with a one-year Cache-Control max-age, so browsers keep images for a year while a changed image gets a new URL. Use it when the origin cannot set long cache lifetimes itself; under CoreFilters it is already on through extend_cache, and rewrite_images produces content-hashed URLs of its own for every image it rewrites.

How it works

Disabling it leaves extend_cache_css and extend_cache_scripts on. Live demo: extend_cache.

When to use it

In CoreFilters, the default RewriteLevel: it runs unless you disable it.
Also switched on by extend_cache.
Risk rating on these docs: Generally safe.

Risks

The Image filters page lists no specific risks for this filter. If a page misbehaves with it, DisableFilters extend_cache_images turns it off for the scope you set it in.

Configuration

Enable it in the module configuration, at server, virtual-host or location scope:

Apache

ModPagespeedEnableFilters extend_cache_images

nginx

pagespeed EnableFilters extend_cache_images;

IIS (pagespeed.config)

pagespeed EnableFilters extend_cache_images

It is on by default under CoreFilters; to turn it off:

ModPagespeedDisableFilters extend_cache_images   # Apache
pagespeed DisableFilters extend_cache_images;   # nginx
pagespeed DisableFilters extend_cache_images   # IIS

On the worker

The worker runs its own pipeline, configured by flags. Its equivalent of this filter is the cache extension transform. Always-on under pagespeed on;.

Scoping, ForbidFilters and the thresholds filters read: Choosing filters .

Frequently asked questions

What does the extend_cache_images filter do?: Core filter, one of the three members of extend_cache. Rewrites image URLs to content-hashed .pagespeed.ce. URLs served with a one-year Cache-Control max-age, so browsers keep images for a year while a changed image gets a new URL. Use it when the origin cannot set long cache lifetimes itself; under CoreFilters it is already on through extend_cache, and rewrite_images produces content-hashed URLs of its own for every image it rewrites.
Is extend_cache_images enabled by default?: Yes. extend_cache_images is in CoreFilters, the default RewriteLevel, so it runs unless you turn it off with DisableFilters.
How do I turn off extend_cache_images?: Add ModPagespeedDisableFilters extend_cache_images on Apache or pagespeed DisableFilters extend_cache_images; on nginx. On IIS, add pagespeed DisableFilters extend_cache_images to pagespeed.config.

convert_gif_to_png — Convert GIF to PNG
convert_jpeg_to_avif — Convert JPEG to AVIF
convert_jpeg_to_progressive — Progressive JPEG
convert_jpeg_to_webp — Convert JPEG to WebP
convert_png_to_jpeg — Convert PNG to JPEG
convert_to_avif_animated — Animated AVIF
convert_to_avif_lossless — Lossless AVIF
convert_to_webp_animated — Animated WebP

This page is drawn from the extend_cache_images entry on Image filters. Every filter in one table: PageSpeed filters.