Add documentation for all PDF tools

docs/tools/compress-pdf.md

@@ -0,0 +1,69 @@
+---
+title: Compress PDF
+description: Reduce PDF file size by up to 90% with smart compression algorithms. Supports batch processing and custom quality settings.
+---
+
+# Compress PDF
+
+Shrink your PDF files without destroying them. BentoPDF offers two distinct compression algorithms -- one for text-heavy documents, another for photo-heavy scans -- so you get meaningful size reduction regardless of what your PDF contains.
+
+## How It Works
+
+1. Upload one or more PDFs by clicking the drop zone or dragging files in.
+2. Select a **Compression Algorithm** -- Condense or Photon.
+3. Pick a **Compression Level** from Light to Extreme.
+4. Optionally toggle **Convert to Grayscale** or expand **Custom Settings** for fine-grained control.
+5. Click **Compress PDF**. For multiple files, you get a single ZIP download.
+
+## Compression Algorithms
+
+### Condense (Recommended)
+
+The default algorithm. It removes dead weight from the PDF structure, recompresses images at a target DPI, subsets fonts to strip unused glyphs, and removes embedded thumbnails. The PDF stays fully functional -- text remains selectable, links keep working.
+
+Condense requires the PyMuPDF WASM engine.
+
+### Photon (For Photo-Heavy PDFs)
+
+Photon renders each page to a JPEG image and reassembles them into a new PDF. This works well for scanned documents or image-heavy files where Condense cannot squeeze much out. The trade-off is that text becomes non-selectable and hyperlinks stop working.
+
+## Compression Levels
+
+| Level          | Image Quality | DPI Target | Best For                       |
+| -------------- | ------------- | ---------- | ------------------------------ |
+| **Light**      | 90%           | 150        | Preserving visual quality      |
+| **Balanced**   | 75%           | 96         | Everyday documents             |
+| **Aggressive** | 50%           | 72         | Email attachments, web uploads |
+| **Extreme**    | 30%           | 60         | Maximum size reduction         |
+
+## Custom Settings
+
+Expand the Custom Settings panel to override preset values:
+
+- **Output Quality** (1-100%) -- JPEG quality for recompressed images
+- **Resize Images To** (DPI) -- target resolution for downsampled images
+- **Only Process Above** (DPI) -- images below this threshold are left untouched
+- **Remove metadata** -- strips document info fields
+- **Subset fonts** -- removes unused glyphs from embedded fonts
+- **Remove embedded thumbnails** -- drops preview images stored inside the PDF
+
+## Use Cases
+
+- Bringing a 50 MB report under an email attachment limit
+- Optimizing marketing PDFs for faster website downloads
+- Archiving large document sets where storage costs matter
+- Preparing scanned contracts for a document management system
+- Reducing mobile data usage when sharing PDFs over messaging apps
+
+## Tips
+
+- Start with Balanced. If the result is still too large, step up to Aggressive before trying Extreme.
+- Use Photon only when Condense produces minimal savings -- it permanently removes text selection.
+- The grayscale toggle alone can cut file size substantially for color-heavy documents.
+
+## Related Tools
+
+- [Linearize PDF](./linearize-pdf) -- optimize the compressed PDF for fast web viewing
+- [Rasterize PDF](./rasterize-pdf) -- convert pages to images at a specific DPI
+- [Repair PDF](./repair-pdf) -- fix a PDF that broke during compression elsewhere
+- [Remove Metadata](./remove-metadata) -- strip hidden data for privacy