# Recompress JPEG (recompress_jpeg) JPEG-specific recompression. How the mod_pagespeed recompress_jpeg filter works, when to use it, its risks and the Apache, nginx and IIS directives. Canonical URL: https://modpagespeed.com/docs/filters/recompress_jpeg/ - Category: Image - CoreFilters: Yes - OptimizeForBandwidth: Yes - Risk: Generally safe `recompress_jpeg` re-encodes JPEG images that reach it. It runs after the conversion candidates: a JPEG that was not converted to WebP or AVIF for this request is re-encoded at `JpegRecompressionQuality`, which defaults to -1, meaning it follows `ImageRecompressionQuality` (default 85). Only when `ImageRecompressionQuality` is itself -1 does the module keep the source file's own quality. ## How it works The recompression filters reduce image file size by re-encoding images at an optimal quality level. They preserve visual quality while removing encoding inefficiencies, and each one handles exactly the format its name says, so a format you do not want re-encoded can be turned off by name without touching the others. ### How each format is recompressed `recompress_jpeg` keeps a re-encode only when it is smaller than the original by the margin `ImageLimitOptimizedPercent` sets (default 100: any reduction at all), and a losing re-encode is remembered so the same JPEG is not re-encoded on every request. The filter is a CoreFilter through `rewrite_images` and also part of OptimizeForBandwidth; disabling it by name while keeping the compound on leaves the other formats recompressing. `recompress_images` is a convenience filter that enables `recompress_jpeg`, `recompress_png`, and `recompress_webp` together with `convert_gif_to_png`, `convert_jpeg_to_progressive`, `convert_jpeg_to_webp`, `convert_png_to_jpeg`, `jpeg_subsampling`, `strip_image_color_profile`, and `strip_image_meta_data`. ## When to use it - In CoreFilters, the default RewriteLevel: it runs unless you disable it. - Part of OptimizeForBandwidth, the level that optimizes resources without changing their URLs. - Also switched on by [`recompress_images`](https://modpagespeed.com/docs/filters/recompress_images/) and [`rewrite_images`](https://modpagespeed.com/docs/filters/rewrite_images/). - Risk rating on these docs: **Generally safe**. ## Risks Recompression is lossy. Setting quality too low produces visible artifacts. The default values are conservative and safe for most content. Photographic content can tolerate lower quality than screenshots or text-heavy images. ## Configuration Enable it in the module configuration, at server, virtual-host or location scope: **Apache** ```apache ModPagespeedEnableFilters recompress_jpeg ``` **nginx** ```nginx pagespeed EnableFilters recompress_jpeg; ``` **IIS (pagespeed.config)** ```text pagespeed EnableFilters recompress_jpeg ``` It is on by default under CoreFilters; to turn it off: ```text ModPagespeedDisableFilters recompress_jpeg # Apache pagespeed DisableFilters recompress_jpeg; # nginx pagespeed DisableFilters recompress_jpeg # IIS ``` | Parameter | Default | Description | | --------------------------- | ------- | --------------------------------------------------------------------------------- | | `ImageRecompressionQuality` | 85 | General quality level for recompressed images (-1 to 100; -1 uses source quality) | | `JpegRecompressionQuality` | -1 | JPEG-specific quality; -1 uses `ImageRecompressionQuality` | | `WebpRecompressionQuality` | 80 | WebP quality level | ### On the worker The worker runs its own pipeline, configured by flags. Its equivalent of this filter is the [image pipeline](https://modpagespeed.com/docs/worker-configuration/#image-pipeline) transform. Always-on baseline under `pagespeed on;`; there is no per-transform off switch. Scoping, `ForbidFilters` and the thresholds filters read: [Choosing filters](https://modpagespeed.com/docs/filter-selection/). ## Frequently asked questions **What does the recompress_jpeg filter do?** `recompress_jpeg` re-encodes JPEG images that reach it. It runs after the conversion candidates: a JPEG that was not converted to WebP or AVIF for this request is re-encoded at `JpegRecompressionQuality`, which defaults to -1, meaning it follows `ImageRecompressionQuality` (default 85). Only when `ImageRecompressionQuality` is itself -1 does the module keep the source file's own quality. **Is recompress_jpeg enabled by default?** Yes. `recompress_jpeg` is in CoreFilters, the default RewriteLevel, so it runs unless you turn it off with `DisableFilters`. It is also part of the OptimizeForBandwidth level. **How do I turn off recompress_jpeg?** Add `ModPagespeedDisableFilters recompress_jpeg` on Apache or `pagespeed DisableFilters recompress_jpeg;` on nginx. On IIS, add `pagespeed DisableFilters recompress_jpeg` to pagespeed.config. ## Related filters - [`recompress_images`](https://modpagespeed.com/docs/filters/recompress_images/): Recompress images - [`recompress_png`](https://modpagespeed.com/docs/filters/recompress_png/): Recompress PNG - [`recompress_webp`](https://modpagespeed.com/docs/filters/recompress_webp/): Recompress WebP - [`convert_gif_to_png`](https://modpagespeed.com/docs/filters/convert_gif_to_png/): Convert GIF to PNG - [`convert_jpeg_to_avif`](https://modpagespeed.com/docs/filters/convert_jpeg_to_avif/): Convert JPEG to AVIF - [`convert_jpeg_to_progressive`](https://modpagespeed.com/docs/filters/convert_jpeg_to_progressive/): Progressive JPEG - [`convert_jpeg_to_webp`](https://modpagespeed.com/docs/filters/convert_jpeg_to_webp/): Convert JPEG to WebP - [`convert_png_to_jpeg`](https://modpagespeed.com/docs/filters/convert_png_to_jpeg/): Convert PNG to JPEG This page is drawn from the [recompress_jpeg entry on Image filters](https://modpagespeed.com/docs/image-filters/#recompress_jpeg). Every filter in one table: [PageSpeed filters](https://modpagespeed.com/docs/filters/).