Seedream Image Generation

Generate and edit images via Volcengine Doubao-Seedream API using {baseDir}/scripts/generate_image.py.

This skill wraps the Volcengine Ark Image Generation API. It supports text-to-image, image editing, multi-reference fusion, sequential/group generation, PNG output, prompt optimization, web search, and streaming output. Works with Seedream 5.0-lite (default), 4.5, and 4.0 models.

Quick start

# Text to image (simplest form)
uv run {baseDir}/scripts/generate_image.py --prompt "一只赛博朋克风格的猫"

# Image editing (with reference image)
uv run {baseDir}/scripts/generate_image.py --prompt "变为水墨画风格" --image "https://example.com/photo.jpg"

# Multi-reference fusion
uv run {baseDir}/scripts/generate_image.py --prompt "融合风格" --image "https://a.jpg" --image "https://b.jpg"

# Group/sequential generation
uv run {baseDir}/scripts/generate_image.py --prompt "四格漫画" --sequential --max-images 4

# List available models
uv run {baseDir}/scripts/generate_image.py --list-models

API key

Set VOLC_API_KEY env var or pass --api-key. Never hardcode keys in scripts.

export VOLC_API_KEY="your-key"
# or
--api-key your-key

Models

Default model: doubao-seedream-5-0-260128 (5.0-lite). Override with --model.

Model comparison

When to choose which model

• 5.0-lite (default) — Best overall quality. Only model supporting PNG output, 3K resolution, and web search. Use for most tasks.
• 4.5 — High quality, slightly different style. Good alternative to 5.0-lite.
• 4.0 — Supports --prompt-optimization fast for quicker results. Good for rapid iteration. Also supports 1K for smaller/faster generation.

Size and resolution

Two ways to specify size (cannot mix):

Method 1 — Preset (recommended for most cases):

--size 2K    # 2048x2048 (default)
--size 3K    # 3072x3072 (5.0-lite only)
--size 4K    # 4096x4096 (all models)
--size 1K    # 1024x1024 (4.0 only)

Method 2 — Pixel format (for custom aspect ratios):

--size 3840x2160    # 16:9 widescreen
--size 1080x1920    # 9:16 portrait
--size 1200x1200    # custom square

Resolution table (preset sizes × aspect ratios)

When using preset sizes, the model picks the best aspect ratio based on your prompt. For precise control, use pixel format.

Pixel format constraints

• 5.0-lite: total pixels ∈ [3,686,400 ~ 16,777,216], aspect ratio ∈ [1/16 ~ 16]
• 4.5: total pixels ∈ [3,686,400 ~ 16,777,216], aspect ratio ∈ [1/16 ~ 16]
• 4.0: total pixels ∈ [921,600 ~ 16,777,216], aspect ratio ∈ [1/16 ~ 16]

Examples:

• ✅ 3840x2160 → 8,294,400 pixels, ratio 1.78 → valid for all models
• ✅ 2160x3840 → same pixels, ratio 0.56 → valid for all models
• ❌ 1500x1500 → 2,250,000 pixels \x3C 3,686,400 minimum → invalid for 5.0-lite/4.5

Flags reference

Required

• --prompt — Text description for image generation. Supports Chinese and English. Recommended under 300 Chinese characters or 600 English words.

Model and size

• --model — Model ID (default: doubao-seedream-5-0-260128)
• --size — Preset (1K/2K/3K/4K) or pixel (WIDTHxHEIGHT, default: 2K)

Image input

• --image — Reference image URL or base64. Repeat for multiple images (max 14 total). Used for image editing and multi-reference fusion.

Supported input formats: jpeg, png, webp, bmp, tiff, gif, heic, heif. Constraints: max 30MB per image, max 60MP (width×height), aspect ratio [1/16, 16].

Output control

• --output-format — jpeg (default) or png (5.0-lite only)
• --response-format — url (default, 24h valid) or b64_json (base64 encoded)
• --watermark / --no-watermark — Enable/disable "AI生成" watermark (default: enabled)

Generation mode

• --sequential — Enable group/sequential generation (multiple related images)
• --max-images — Number of images in sequential mode (1-15, default: 1)
• --stream — Enable streaming output (get results as generated)
• --web-search — Enable web search for real-time info (5.0-lite only). Uses tools: [{type: "web_search"}] API parameter.

Prompt enhancement

• --prompt-optimization — standard (all models) or fast (4.0 only). Rewrites prompt for better results.

Utilities

• --list-models — List available Seedream models and their capabilities
• --api-key — Volcengine API key (or set VOLC_API_KEY env)

Use cases with complete examples

1. Text to image (basic)

uv run {baseDir}/scripts/generate_image.py --prompt "充满活力的特写肖像，模特眼神犀利，头戴雕塑感帽子，色彩拼接丰富，Vogue杂志封面美学"

2. Text to image (with specific size)

# 4K landscape
uv run {baseDir}/scripts/generate_image.py --prompt "壮丽的山川日出，金色阳光穿过云层" --size 4K

# Custom widescreen
uv run {baseDir}/scripts/generate_image.py --prompt "赛博朋克城市夜景" --size 3840x2160

# Portrait for phone wallpaper
uv run {baseDir}/scripts/generate_image.py --prompt "极简抽象艺术" --size 1080x1920

3. Image editing (single reference)

uv run {baseDir}/scripts/generate_image.py \
  --prompt "保持模特姿势和构图不变，将服装材质从银色金属改为完全透明的清水" \
  --image "https://example.com/original.jpg"

4. Multi-reference fusion

# Combine 2 images
uv run {baseDir}/scripts/generate_image.py \
  --prompt "将图1的服装换为图2的服装" \
  --image "https://example.com/person.jpg" \
  --image "https://example.com/clothing.jpg"

# Combine 3+ images
uv run {baseDir}/scripts/generate_image.py \
  --prompt "融合这三张图的风格特征，生成统一视觉" \
  --image "https://example.com/1.jpg" \
  --image "https://example.com/2.jpg" \
  --image "https://example.com/3.jpg"

5. Sequential/group generation

# Generate 4 related images
uv run {baseDir}/scripts/generate_image.py \
  --prompt "生成一组电影级科幻写实风的4张影视分镜" \
  --sequential --max-images 4

# With reference image
uv run {baseDir}/scripts/generate_image.py \
  --prompt "参考这张图，生成同角色在早晨、中午、晚上的连续画面" \
  --image "https://example.com/character.jpg" \
  --sequential --max-images 3

6. PNG output

uv run {baseDir}/scripts/generate_image.py \
  --prompt "高清产品图，白色背景，专业摄影灯光" \
  --output-format png

7. Prompt optimization

# Standard mode (higher quality, all models)
uv run {baseDir}/scripts/generate_image.py \
  --prompt "一只猫" \
  --prompt-optimization standard

# Fast mode (quicker, 4.0 only)
uv run {baseDir}/scripts/generate_image.py \
  --prompt "一只猫" \
  --model doubao-seedream-4-0-250828 \
  --prompt-optimization fast

8. Web search (real-time info, 5.0-lite only)

# Weather forecast image
uv run {baseDir}/scripts/generate_image.py \
  --prompt "制作一张上海未来5日的天气预报图，扁平化插画风格" \
  --web-search

# Current events
uv run {baseDir}/scripts/generate_image.py \
  --prompt "2026年最流行的时尚趋势海报" \
  --web-search

9. No watermark (commercial use)

uv run {baseDir}/scripts/generate_image.py \
  --prompt "产品宣传图，专业商业摄影" \
  --no-watermark

Prompt writing tips

• Language: Supports Chinese and English. English tends to produce slightly better results for complex scenes, but Chinese works well too.
• Length: Under 300 Chinese characters or 600 English words recommended. Too long → model may ignore some details.
• Specificity: Be specific. "赛博朋克风格的猫，霓虹灯光，雨夜街道，4K，电影感" > "一只猫"
• Style keywords: Append style terms for control:
  • 水墨画风格 (ink painting)
  • 油画风格 (oil painting)
  • 写实摄影 (photorealistic)
  • 扁平化插画 (flat illustration)
  • 电影感 (cinematic)
  • 杂志封面 (magazine cover)
• Structure: For complex scenes, describe subject → composition → style → lighting → quality

Output interpretation

Script stdout contains exactly one of:

• MEDIA_URL: \x3Curl> — Image download link. Valid for 24 hours. Use markdown: ![description](url)
• MEDIA_B64: \x3Cbase64> — Base64 encoded image data (when --response-format b64_json)
• ERROR: \x3Cmsg> — Error occurred. Check message for details.

Error handling

Workflow

1. Parse user's image request to determine: text-to-image, editing, fusion, or sequential
2. Choose appropriate model (default: 5.0-lite unless specific need)
3. Determine size: use preset for general, pixel format for specific aspect ratio
4. Build and run the command with appropriate flags
5. Parse stdout for MEDIA_URL: or MEDIA_B64:
6. Display to user as markdown image or file
7. If URL, remind user it expires in 24h if they need to save it

Input image requirements

• Formats: jpeg, png, webp, bmp, tiff, gif, heic, heif
• Max size: 30MB per image
• Max pixels: 60,000,000 (width × height)
• Aspect ratio: [1/16, 16]
• Min dimension: > 14px per side
• Max images: 14 per request
• Total: input images + output images ≤ 15

Rate limits

All models: 500 images per minute (IPM). Plan batch operations accordingly.

Full reference

For detailed API parameter docs, see references/REFERENCE.md.