How it works
The “Light” level rewrites the file more compactly without touching the content. “Medium” and “Strong” convert each page into a JPEG image (150 or 100 dpi): very effective on scans and photo-heavy documents, but the text is no longer selectable. Use them when size matters more than text search.
FAQ
Why does Light barely reduce anything?
Because the PDF was already well built. Gains then come only from images: switch to Medium.
Does text remain selectable?
With Light, yes. With Medium and Strong, no: pages become images.
What size should I aim for on an official portal?
Most accept 2–5 MB. Medium is usually enough for a 10–20 page scan.