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Lake AI Service

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Image processing
Image compression
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Image compression

Operator ID: daft.las.functions.image.image_compress.ImageCompress

Operator introduction

Description

Image compression processor that supports multiple interpolation algorithms and various input and output formats.

Key features

  • Input formats:
    • URL address (image_url)
    • Base64 encoding (image_base64)
    • Binary stream (image_binary)
  • Compression and scaling:
    • Quality compression (quality parameter)
    • Size scaling (target_size or keep original size)
    • Multiple interpolation algorithms: nearest / bilinear / bicubic / lanczos
  • Output modes:
    • Returns the Base64-encoded string of the compressed image
    • Optionally save the image to TOS
    • Optionally save the image to a local directory
  • Format adaptation:
    • JPEG: quality compression + RGBA to RGB conversion
    • PNG: lossless compression (compress_level) + preserve alpha channel
    • WebP: quality/lossless compression + preserve alpha channel

Caution and prerequisites

Details

Caution and prerequisites

Costs

Before calling an operator, you need to understand the model invocation costs associated with using the operator. For details, see Large model invocation billing.

Authentication (API Key)

Before calling an operator, you need to generate an API Key for operator invocation. It is recommended to configure the API Key as an environment variable to ensure safer operator calls. For details, see Obtain and configure API Key.

BaseURL

Before calling an operator, you need to determine the BaseURL for operator invocation based on the region where your current LAS service is deployed. This is used to configure the path parameter values for operator calls.
For details, see Obtain the Base URL. The Examples below are for reference only; when making actual calls, replace the path values with those corresponding to your region.

Daft invocation

Operator parameters

Input

Input column name

Description

image

An array containing input images, supporting URL, Base64, and binary formats

image_name

Optional parameter. An array containing image identifier names, used to generate output file names.

Output

An array of dictionaries containing processing results. Each element includes:

  • base64: Base64-encoded string of the compressed image;
  • image_path: Local/TOS storage path (valid when output directory is configured)

Parameters

If a parameter does not have a default value, it is required.

Parameter name

Type

Default value

Description

image_suffix

str

.jpg

Suffix of the output file.
Description: File suffix used when saving to TOS or local. Must be a supported format.
Optional values: [".jpg", ".jpeg", ".png", ".webp"]
Default value: ".jpg"

output_dir

str

""

Output folder path for saving images.
Description: Output path for saving compressed images. If empty, images are not saved to output. Supports TOS and local paths.
Default value: ""

image_src_type

str

image_url

Format type of the input image.
Optional values: ["image_url", "image_base64", "image_binary"]
Default value: "image_url"

target_size

list

None

Size of the compressed image.
Description: Format is [width, height]; None means keep original size.
Default value: None

quality

int

85

Compression quality parameter (adapted for different formats):

  • JPEG/WebP: 1-100 (higher value means better quality)
  • PNG: Mapped to compress_level (1→9, 100→0)

Default value: 85

method

str

lanczos

Interpolation algorithm used for scaling.
Optional values: ["nearest", "bilinear", "bicubic", "lanczos"]
Default value: "lanczos"

Examples

The following code demonstrates how to use daft to run the operator for image compression.

from __future__ import annotations

import os

import daft
from daft import col
from daft.las.functions.image.image_compress import ImageCompress
from daft.las.functions.udf import las_udf

if __name__ == "__main__":
    # Content will be saved to the specified TOS path. Therefore, environment variables must be set to ensure write permissions to TOS, including: ACCESS_KEY, SECRET_KEY, TOS_ENDPOINT, TOS_REGION, TOS_TEST_DIR
    TOS_DIR = os.getenv("TOS_TEST_DIR", "tos_bucket")
    output_tos_dir = f"tos://{TOS_DIR}/image/image_compress"

    if os.getenv("DAFT_RUNNER", "native") == "ray":
        import logging

        import ray

        def configure_logging():
            logging.basicConfig(
                level=logging.INFO,
                format="%(asctime)s - %(name)s - %(levelname)s - %(message)s",
                datefmt="%Y-%m-%d %H:%M:%S.%s".format(),
            )
            logging.getLogger("tracing.span").setLevel(logging.WARNING)
            logging.getLogger("daft_io.stats").setLevel(logging.WARNING)
            logging.getLogger("DaftStatisticsManager").setLevel(logging.WARNING)
            logging.getLogger("DaftFlotillaScheduler").setLevel(logging.WARNING)
            logging.getLogger("DaftFlotillaDispatcher").setLevel(logging.WARNING)

        ray.init(dashboard_host="0.0.0.0", runtime_env={"worker_process_setup_hook": configure_logging})
        daft.set_runner_ray()
    daft.set_execution_config(actor_udf_ready_timeout=600)
    daft.set_execution_config(min_cpu_per_task=0)

    tos_dir_url = os.getenv("TOS_DIR_URL", "las-cn-beijing-public-online.tos-cn-beijing.volces.com")
    samples = {
        "image": [f"https://{tos_dir_url}/public/shared_image_dataset/cat.png"],
        "image_name": ["cat_ip_adapter"],
    }
    image_suffix = ".jpg"
    image_src_type = "image_url"
    target_size = [200, 200]
    quality = 85
    method = "lanczos"
    local_dir = ""
    ds = daft.from_pydict(samples)
    ds = ds.with_column(
        "image_compress",
        las_udf(
            ImageCompress,
            construct_args={
                "image_suffix": image_suffix,
                "output_dir": output_tos_dir,
                "image_src_type": image_src_type,
                "target_size": target_size,
                "quality": quality,
                "method": method,
            },
            batch_size=1,
        )(col("image"), col("image_name")),
    )
    ds.show()
# ╭────────────────────────────────┬────────────────┬────────────────────────────────────────────╮
# │ image                          ┆ image_name     ┆ image_compress                             │
# │ ---                            ┆ ---            ┆ ---                                        │
# │ String                         ┆ String         ┆ Struct[base64: String, image_path: String] │
# ╞════════════════════════════════╪════════════════╪════════════════════════════════════════════╡
# │ https://las-ai-qa-online.tos-… ┆ cat_ip_adapter ┆ {base64: /9j/4AAQSkZJRgABAQAA…             │
# ╰────────────────────────────────┴────────────────┴────────────────────────────────────────────╯
Last updated: 2026.05.24 15:20:27