Byted Tos Image Process

Documents

byted-tos-image-process

Byted Tos Image Process is an Agent Skill for documents published in the bytedance/agentkit-samples repository on GitHub: a SKILL.md instruction file an AI agent can load to do this task.

Inspects and transforms images stored in Volcengine TOS: read metadata, convert formats, resize, draw points and lines, perform zoom-style resize plus crop, add visible text or image watermarks, embed blind watermarks, and AI-powered image understanding (VLM). Use this skill when the user needs to get image dimensions or format info, convert between JPEG/PNG/WebP, resize or crop images, annotate images with markers or boxes, add watermarks, extract blind watermarks, describe image content, perform OCR, detect faces, or answer visual questions — even if they don't explicitly mention 'image processing' or 'TOS'.

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QUICK START

How to use this skill

Bring this guide into your coding agent with a prompt tailored to the tool you use.

Open your project in Codex.
Copy and paste the prompt below.
Review files and risks before approving any action.

Prompt to paste

Inspect the Agent Skill at https://github.com/bytedance/agentkit-samples/blob/HEAD/skills/byted-tos-image-process/SKILL.md and all supporting files. Report provenance, permissions, scripts, dependencies, and security risks. Propose an exact installation into .agents/skills/byted-tos-image-process, but wait for my approval before writing files or running scripts.

Copying this prompt does not install or run the skill. Review third-party files before use.

Volcengine TOS Image Process

Inspect and transform images stored in Volcengine TOS — metadata, format conversion, resize, watermark, blind watermark, and AI-powered image understanding.

Setup (once per environment)

Install dependencies on first use:

cd {baseDir}
pip install -r {baseDir}/requirements.txt

Then run scripts with Python 3.7+:

python3 {baseDir}/scripts/<script>.py <args>

If you see a ModuleNotFoundError for tos, reinstall dependencies.

Environment Variables

This skill relies on the TOS identity declared in the metadata block. Common runtime variables are:

Environment Variable	Required	Description
`TOS_ACCESS_KEY`	Yes	TOS access key ID
`TOS_SECRET_KEY`	Yes	TOS secret access key
`TOS_ENDPOINT`	Yes	TOS endpoint URL
`TOS_REGION`	Yes	TOS region
`TOS_BUCKET`	Yes	Source bucket that stores the image
`TOS_OBJECT_KEY`	No	Source object key of the image. Can be overridden with `--key`
`TOS_SECURITY_TOKEN`	No	STS session token when using temporary credentials
`TOS_SAVEAS_BUCKET`	No	Default target bucket for saving processed results
`TOS_SAVEAS_OBJECT_PREFIX`	No	Default key prefix for saving processed results

Quick start (common tasks)

# Read image metadata
python3 {baseDir}/scripts/image_info.py --key photo.jpg

# Convert to WebP
python3 {baseDir}/scripts/image_format.py --key photo.jpg --f webp --output converted.webp

# Resize to width 500
python3 {baseDir}/scripts/image_resize.py --key photo.jpg --w 500 --output resized.jpg

# Draw points and connecting lines
python3 {baseDir}/scripts/image_draw.py --key photo.jpg \
  --points 50x50-200x120-320x220 --line --color FF0000 --output draw.jpg

# Zoom by resize + crop
python3 {baseDir}/scripts/image_zoom.py --key photo.jpg \
  --resize-w 1200 --crop-w 500 --crop-h 400 --gravity center --output zoom.jpg

# Add visible text watermark
python3 {baseDir}/scripts/image_watermark.py --key photo.jpg \
  --text "My Brand" --font fangzhengshusong --color FF0000 --size 72 \
  --gravity center --output watermarked.jpg

# Embed blind watermark (requires ≥512×512 image and account permission)
python3 {baseDir}/scripts/image_blindwatermark.py --key photo.jpg \
  --kv text=HelloBlind --output blind.jpg

# Run a custom process string
python3 {baseDir}/scripts/image_process.py --key photo.jpg \
  --process "image/resize,w_300,h_300,m_fill" --output filled.jpg

# AI-powered image understanding (describe, OCR, face detection, etc.)
python3 {baseDir}/scripts/image_understanding.py --key photo.jpg \
  --prompt "Describe this image in detail"
python3 {baseDir}/scripts/image_understanding.py --key document.png \
  --prompt "识别图片中的所有文字内容"

Available scripts

Script	Purpose
`scripts/image_info.py`	Read image metadata (format, dimensions, size). Falls back to local parsing when TOS returns raw bytes.
`scripts/image_format.py`	Convert format (jpg, png, webp) with optional quality setting.
`scripts/image_resize.py`	Resize by width/height/mode.
`scripts/image_draw.py`	Draw points and optional connecting lines on an image with `image/draw`.
`scripts/image_zoom.py`	Build agent-friendly zoom results by chaining `image/resize` and `crop`.
`scripts/image_watermark.py`	Add visible text or image watermark with positioning, rotation, tiling, and opacity.
`scripts/image_blindwatermark.py`	Embed blind watermark. Requires account-level permission and image ≥512×512 px.
`scripts/image_process.py`	Pass any raw `image/...` process string.
`scripts/image_understanding.py`	AI-powered image understanding via VLM (doubao-seed-1.6-vision). Supports description, OCR, face detection, and visual Q&A through natural language prompts. Requires account whitelist.

All scripts support --key to override TOS_OBJECT_KEY, --output for local save, and --saveas-bucket/--saveas-object for TOS-to-TOS persistence. Most scripts also support --json for machine-readable output, and the process-building scripts support --dry-run to preview the resolved request. Run any script with -h for full usage.

Out of scope

Editing images with local desktop tooling outside TOS.
Video or document processing (use byted-tos-video-process or byted-tos-doc-process).
Non-TOS storage providers.

Rules

Authentication: Authentication is provided by the TOS identity declared in the metadata block above. Object selection can be overridden per script with --key.
Parameter source of truth: The exact process string syntax is defined by official Volcengine TOS documentation. When uncertain, check REFERENCE.md.
Watermark encoding: Text and font parameters in image/watermark require URL-safe Base64 encoding. The watermark script handles this automatically when you pass --text and --font.
Blind watermark constraints: The source image must be at least 512×512 pixels, and the account must have the blind watermark capability enabled. If the capability is missing, the script exits with [SKIP] (use --strict to fail hard).
Image understanding: Uses image/understanding with the doubao-seed-1.6-vision VLM model. The --prompt parameter is required. Supports description, OCR, face detection, and any visual Q&A task. Requires account whitelist. Response time is typically 10-60 seconds.
Language: Reply in the user's preferred language.