PDFを5MBに圧縮

No — compression works by re-rendering each page as an image at a lower quality, so any selectable text becomes part of that image. If you need to keep text selectable, use our PDF OCR tool instead after compressing, or compress less aggressively.

"Recommended" balances size and readability for most documents. Use "Extreme" only when the absolute smallest file size matters more than visual quality, like for email attachment limits.

Yes — scanned documents and image-heavy PDFs see the biggest size reduction, since that's exactly the kind of content this tool re-compresses.