Add documentation for all PDF tools

docs/tools/pdf-to-webp.md

@@ -0,0 +1,43 @@
+---
+title: PDF to WebP
+description: Convert PDF pages to WebP images with adjustable quality. Smaller file sizes than JPG at comparable visual quality.
+---
+
+# PDF to WebP
+
+Converts each page of a PDF into a WebP image. WebP typically produces files 25-35% smaller than JPG at the same perceived quality, making it a strong choice for web use.
+
+## How It Works
+
+1. Upload a PDF by clicking the drop zone or dragging a file onto it.
+2. Adjust the **Quality** slider.
+3. Click **Convert** to process the file.
+4. A single `.webp` file or a ZIP archive downloads automatically.
+
+## Options
+
+- **Quality** -- a slider from 0% to 100% (default 85%). Controls the lossy compression level. Higher values retain more detail.
+
+Pages render at 2x scale internally, producing images at roughly double the PDF's native dimensions.
+
+## Output Format
+
+- **Single page**: `filename.webp`
+- **Multiple pages**: `filename_webps.zip` containing `page_1.webp`, `page_2.webp`, etc.
+
+## Use Cases
+
+- Preparing page previews for websites where bandwidth matters.
+- Generating lightweight image versions of flyers or brochures for social media.
+- Batch-converting multi-page documents into a web-optimized image set.
+
+## Tips
+
+- WebP is supported in all modern browsers. For legacy compatibility, fall back to [PDF to JPG](./pdf-to-jpg).
+- A quality of 80-85% is usually indistinguishable from the original on screen while keeping file sizes small.
+
+## Related Tools
+
+- [PDF to JPG](./pdf-to-jpg)
+- [PDF to PNG](./pdf-to-png)
+- [PDF to BMP](./pdf-to-bmp)