Thumbnails¶
Generate screenshot-based thumbnail images for notebooks, used by OpenGraph previews and cards in gallery mode.
marimo export thumbnail generate notebook.py
## Output location
By default, thumbnails are written to:
This is the default OpenGraph thumbnail path used by [OpenGraph previews](opengraph.md).
## Requirements
!!! note "Requires Playwright"
Thumbnail generation uses Playwright and Chromium:
```bash
python -m pip install playwright
python -m playwright install chromium
```
## Generate thumbnails
You can generate a thumbnail for a single notebook:
```bash
marimo tools thumbnails generate notebook.py
Or generate thumbnails for all notebooks in a directory:
When you pass a directory, marimo scans it for marimo notebooks and skips non-notebook files (for example README.md).
Execution modes¶
By default, thumbnails are generated without executing the notebook (fast; no outputs). You can opt into execution if you want outputs included.
Requires uv
--sandbox runs the notebook in an isolated environment and installs dependencies from inline script metadata (PEP 723). See Inlining dependencies.
Sandbox only applies with execution
--sandbox requires --execute. In --no-execute mode, marimo does not run the notebook, so there are no dependencies to install.
Including code
In --no-execute mode, thumbnails always include code. When using --execute, add --include-code to show code alongside outputs.
Overwriting and custom output paths¶
If a thumbnail already exists, marimo will skip it by default. To replace existing thumbnails:
To write a thumbnail to a specific filename, use --output (single notebook only):
Tuning quality¶
For OpenGraph previews, the default viewport size is 1200x630. marimo also uses a default --scale 2 so thumbnails are crisp at typical OpenGraph resolutions.
To increase output resolution, increase --scale (max 4):
If thumbnails appear blank or partially rendered, increase --timeout-ms to wait longer before the screenshot:
Passing arguments to notebooks¶
To pass CLI args through to the notebook, separate them with --:
For more on passing values to notebooks, see Command Line Arguments.