Question 1

What's the difference between Strong and Light?

Accepted Answer

Strong mode renders each page to a JPEG image and rebuilds the PDF, often shrinking it by 50–90% — but text inside becomes an image and is no longer selectable or searchable. Light mode re-saves the PDF losslessly with object streams; text is preserved but savings are usually only 5–15%.

Question 2

Which mode should I use?

Accepted Answer

Use Strong for scanned documents, image-heavy slide decks, or when you just need a smaller file to email. Use Light when you must preserve selectable/searchable text.

Question 3

Why didn't my PDF get smaller?

Accepted Answer

If your PDF is already mostly text (which is well-compressed by default), Light mode may produce little or no savings. Try Strong mode, or lower the image quality to Low.

Question 4

What does image quality affect?

Accepted Answer

Quality controls both the render resolution (DPI) and JPEG compression level. Low produces the smallest file but visibly blurrier pages; High keeps pages crisp at the cost of size. Medium is a good default.

Question 5

Is my PDF uploaded anywhere?

Accepted Answer

No. The entire compression runs inside your browser using PDF.js and pdf-lib. Your file never leaves your device.

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