# Optimize images without quality loss

Robot: `/image/optimize`

🤖/image/optimize reduces the size of images while maintaining the same visual quality.

With this <dfn>Robot</dfn> it's possible to reduce the file size of your JPEG, PNG, GIF, WEBP and SVG images by up to 80% for big images and 65% for small to medium sized ones — while keeping their original quality!

This <dfn>Robot</dfn> enables you to lower your storage and bandwidth costs, and improves your user experience and monetization by reducing the load time of image-intensive web pages.

It works well together with [🤖/image/resize](/docs/robots/image-resize.md) to bring the full power of resized and optimized images to your website or app.

> [!Note]
> This <dfn>Robot</dfn> accepts all image types and will just pass on unsupported image types unoptimized, including JPEG XL (`.jxl`) images when no smaller optimized result can be produced. Hence, there is no need to set up [🤖/file/filter](/docs/robots/file-filter.md) workflows for this.

> [!Note]
> PNG optimization uses only lossless (optipng) compressors by default. To also enable lossy compression (pngquant), set `lossy: true`. When enabled, both lossy and lossless compressors compete and the smallest result wins, which may cause color shifts in some images.

Stage: ga

## Usage example

Optimize uploaded images:

```json
{
  "steps": {
    "optimized": {
      "robot": "/image/optimize",
      "use": ":original"
    }
  }
}
```

## Parameters

* `interpolate`: Controls whether Assembly Variables are interpolated for individual instruction fields.

  By default, most Robot instruction fields interpolate Assembly Variables. Set this to `false` to treat every instruction field as literal text, or set an individual field path to `false` to treat only that field as literal text. For Robot-specific fields that are literal by default, set this to `true` or set that field path to `true` to opt back into interpolation.

  Use field names such as `path`, or dotted paths such as `ffmpeg.vf` for nested objects.

* `output_meta`: Allows you to specify a set of metadata that is more expensive on CPU power to calculate, and thus is disabled by default to keep your Assemblies processing fast.

  For images, you can add `"has_transparency": true` in this object to extract if the image contains transparent parts and `"dominant_colors": true` to extract an array of hexadecimal color codes from the image.

  For images, you can also add `"blurhash": true` to extract a [BlurHash](https://blurha.sh) string — a compact representation of a placeholder for the image, useful for showing a blurred preview while the full image loads.

  For videos, you can add the `"colorspace": true` parameter to extract the colorspace of the output video.

  For videos, you can also add `"interlaced": true` to detect whether the video is interlaced. This combines the cheap ffprobe `field_order` flag with a bounded `idet` sampling pass over the first frames of the source, exposing `interlaced`, `field_order`, and a diagnostic `interlace_detection` object under `file.meta`. This is computationally expensive and billed accordingly.

  For audio, you can add `"mean_volume": true` to get a single value representing the mean average volume of the audio file.

  You can also set this to `false` to skip metadata extraction and speed up transcoding.

* `user_meta`: Adds custom metadata to each file emitted by this Robot without modifying the file’s contents.

  The values are merged with any existing `user_meta` carried by the input file. If both objects contain the same key, this Robot’s value takes precedence. Assembly Variables are supported, for example `{ "internal_file_id": "${file.id}" }`.

* `result`: Whether the results of this Step should be present in the Assembly Status JSON

* `queue`: Setting the queue to 'batch', manually downgrades the priority of jobs for this step to avoid consuming Priority job slots for jobs that don't need zero queue waiting times

* `force_accept`: Force a Robot to accept a file type it would have ignored.

  By default, Robots ignore files they are not familiar with.
  [🤖/video/encode](/docs/robots/video-encode.md), for
  example, will happily ignore input images.

  With the `force_accept` parameter set to `true`, you can force Robots to accept all files thrown at them.
  This will typically lead to errors and should only be used for debugging or combatting edge cases.

* `ignore_errors`: Ignore errors during specific phases of processing.

  Setting this to `["meta"]` will cause the Robot to ignore errors during metadata extraction.

  Setting this to `["execute"]` will cause the Robot to ignore errors during the main execution phase.

  Setting this to `true` is equivalent to `["meta", "execute"]` and will ignore errors in both phases.

* `use`: Specifies which Step(s) to use as input.

  * You can pick any names for Steps except `":original"` (reserved for user uploads handled by Transloadit)
  * You can provide several Steps as input with arrays:
    ```json
    {
      "use": [
        ":original",
        "encoded",
        "resized"
      ]
    }
    ```
  * You can also tag input Steps with `as` to pass semantic intent to robots:
    ```json
    {
      "use": [
        {
          "name": ":original",
          "as": "image"
        },
        {
          "name": ":original",
          "as": "mask"
        }
      ]
    }
    ```

  > [!Tip]
  > That's likely all you need to know about `use`, but you can view [Advanced use cases](/docs/topics/use-parameter.md).

* `priority`: Provides different algorithms for better or worse compression for your images, but that run slower or faster. The value `"conversion-speed"` will result in an average compression ratio of 18%. `"compression-ratio"` will result in an average compression ratio of 31%.

* `progressive`: Interlaces the image if set to `true`, which makes the result image load progressively in browsers. Instead of rendering the image from top to bottom, the browser will first show a low-res blurry version of the image which is then quickly replaced with the actual image as the data arrives. This greatly increases the user experience, but comes at a loss of about 10% of the file size reduction.

* `preserve_meta_data`: Specifies if the image's metadata should be preserved during the optimization, or not. If it is not preserved, the file size is even further reduced. But be aware that this could strip a photographer's copyright information, which for obvious reasons can be frowned upon.

* `fix_breaking_images`: If set to `true` this parameter tries to fix images that would otherwise make the underlying tool error out and thereby break your <dfn>Assemblies</dfn>. This can sometimes result in a larger file size, though.

* `lossy`: When set to `false` (the default), only lossless PNG optimizers are used, disabling pngquant to preserve color accuracy.

  When set to `true`, both lossy and lossless PNG optimizers compete and the smallest result wins. This allows pngquant, a lossy compressor that reduces PNGs to a 256-color palette, which may cause noticeable color shifts in images with rich color palettes, subtle gradients, or brand-specific colors.

  > [!Note]
  > This parameter only affects PNG optimization. JPEG, GIF, WebP, and SVG optimization is unaffected.