davistroy Slide Generator: Generate Images Step
Generate slide visuals using Gemini Pro from the validated graphics descriptions in the presentation. Uses a unified prompt builder and async batch generation for efficiency.
Pre-loaded Context
Working directory:
!pwd
Available presentation files:
!ls -la *.md 2>/dev/null | grep -i pres || echo "No presentation files found"
Existing images:
!ls -la images/ 2>/dev/null || echo "No images directory yet"
Prerequisites
- Preflight:
sg --versionmust succeed before proceeding — ifsgis missing, stop and tell the user this requires the privatedavistroy/slide-generatorengine (owner-only; see ADR-0008) slide-generatorpackage installedGOOGLE_API_KEYset in environment (Gemini Pro access)- A
presentation.mdfile with validated graphics descriptions - Graphics validation should be run first (
.graphics_validatedmarker)
Input Validation
Required:
<presentation.md>- Path to presentation markdown file
Optional:
--resolution <level>- Image resolution:small,medium,high(default: high)--image-format <fmt>- Output format:png,jpg(default: png)--skip-existing- Don't regenerate images that already exist
Instructions
- Verify prerequisites: Confirm
GOOGLE_API_KEYis set and presentation has validated graphics - Run image generation:
sg generate-images presentation.md --resolution high - Monitor progress: Image generation takes time (~5-10s per image)
- Verify output: Check that images were created in the
images/directory - Report results: Show count of images generated, any failures
How It Works
The image generation step uses:
- Gemini Pro (
gemini-3-pro-image-preview): Google's image generation model - Unified prompt builder:
prompt_builder.pyconstructs optimized prompts from descriptions - Async batch generation: Multiple images generated concurrently via
asyncio - API key in header: Authentication via header (not query param)
- Block reason diagnostics: Clear error messages when generation is blocked
Error Handling
| Error | Cause | Fix |
|---|---|---|
GOOGLE_API_KEY not found |
Missing env var | Set the key |
Image blocked |
Content policy violation | Review and soften the description |
Rate limit |
Too many concurrent requests | Built-in rate limiter handles this |
Generation timeout |
Gemini service slow | Retry; increase SG_API_TIMEOUT |
Cost Estimate
- ~$0.10 per image at high resolution
- Typical 20-slide deck: ~$2.00
Output
The step produces:
- PNG/JPG images in an
images/directory (one per slide) - File names correspond to slide numbers (
slide-01.png,slide-02.png, etc.)
Next Step
After images are generated, build the final PowerPoint:
sg build presentation.md --template generic
Or use /sg-build to continue the pipeline.
Related Gemini Image Path
This step delegates image generation to the external sg CLI (the slide-generator package), which is unbundled and maintained outside this repo. personal-plugin's visual-explainer skill/tool is a separate, in-tree, tested Gemini image path with its own prompt builder and model config — the two are intentionally independent implementations, not a shared library. Future Gemini model or API changes (e.g. a new model ID, auth scheme, or block-reason handling) must be applied in both places: here (via the external sg package) and in plugins/personal-plugin/tools/visual-explainer/.