Image Generation Skill

Generate images in the headless sandbox using Python libraries.

Available Libraries

Matplotlib (charts, plots, graphs)

import matplotlib
matplotlib.use('Agg')  # REQUIRED: headless backend
import matplotlib.pyplot as plt

plt.figure(figsize=(10, 6))
plt.plot([1, 2, 3], [1, 4, 9])
plt.title('My Chart')
plt.savefig('/tmp/chart.png', dpi=150, bbox_inches='tight')

PIL/Pillow (drawing, image manipulation)

from PIL import Image, ImageDraw, ImageFont
img = Image.new('RGB', (400, 300), 'white')
draw = ImageDraw.Draw(img)
draw.rectangle([50, 50, 350, 250], outline='black', width=2)
img.save('/tmp/drawing.png')

CRITICAL: Displaying Images to User

After generating an image, always output it as inline base64 markdown so it renders in chat:

import base64
with open('/tmp/output.png', 'rb') as f:
    b64 = base64.b64encode(f.read()).decode()
print(f'![image](data:image/png;base64,{b64})')

Do this in the same exec call as the image generation. The markdown image tag will render directly in the chat.

Guidelines

• Always use matplotlib.use('Agg') before importing pyplot
• NEVER use turtle, tkinter, pygame, or any GUI library
• Save images to /tmp/ directory
• Always output base64 inline — don't just report the file path
• For charts: use clear labels, titles, and legends
• Install missing packages with pip if needed: pip install matplotlib pillow