Is in_place_optimize_for_browser enabled by default?

No. in_place_optimize_for_browser is not in CoreFilters, the default RewriteLevel; it runs only when you enable it by name with EnableFilters.

How do I enable in_place_optimize_for_browser on Apache and nginx?

Add ModPagespeedEnableFilters in_place_optimize_for_browser on Apache or pagespeed EnableFilters in_place_optimize_for_browser; on nginx. On IIS, add pagespeed EnableFilters in_place_optimize_for_browser to pagespeed.config.

filter · Image filters

In-place browser optimization (in_place_optimize_for_browser)

Q: What does the in_place_optimize_for_browser filter do?

in_place_optimize_for_browser is retired. It used to vary in-place optimized images by the browser's Accept header and add Vary: Accept; in-place optimization no longer produces browser-dependent bytes, so the filter has nothing left to do. The name is still accepted, with a warning, so an existing configuration keeps loading; it is no longer part of OptimizeForBandwidth.

Category:: Image
CoreFilters:: No
OptimizeForBandwidth:: No
Risk:: Not rated

in_place_optimize_for_browser is retired. It used to vary in-place optimized images by the browser’s Accept header and add Vary: Accept; in-place optimization no longer produces browser-dependent bytes, so the filter has nothing left to do. The name is still accepted, with a warning, so an existing configuration keeps loading; it is no longer part of OptimizeForBandwidth.

How it works

Remove it from your configuration.

When to use it

Not in CoreFilters: it runs only when you enable it by name.
Retired: the name is still accepted (with a warning) but has no effect, because in-place optimization no longer varies its output by browser.

Risks

The Vary: Accept header can reduce CDN cache hit rates. Many CDNs handle Vary correctly, but verify with your provider.
Some proxy servers do not respect Vary headers and may serve the wrong format to clients.

Configuration

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

Apache

ModPagespeedEnableFilters in_place_optimize_for_browser

nginx

pagespeed EnableFilters in_place_optimize_for_browser;

IIS (pagespeed.config)

pagespeed EnableFilters in_place_optimize_for_browser

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

Frequently asked questions

What does the in_place_optimize_for_browser filter do?: in_place_optimize_for_browser is retired. It used to vary in-place optimized images by the browser's Accept header and add Vary: Accept; in-place optimization no longer produces browser-dependent bytes, so the filter has nothing left to do. The name is still accepted, with a warning, so an existing configuration keeps loading; it is no longer part of OptimizeForBandwidth.
Is in_place_optimize_for_browser enabled by default?: No. in_place_optimize_for_browser is not in CoreFilters, the default RewriteLevel; it runs only when you enable it by name with EnableFilters.
How do I enable in_place_optimize_for_browser on Apache and nginx?: Add ModPagespeedEnableFilters in_place_optimize_for_browser on Apache or pagespeed EnableFilters in_place_optimize_for_browser; on nginx. On IIS, add pagespeed EnableFilters in_place_optimize_for_browser 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 in_place_optimize_for_browser entry on Image filters. Every filter in one table: PageSpeed filters.