How to reduce PDF file size (and when you should not)

Almost every oversized PDF is oversized for the same reason: it contains images. A 40-page text-only report is often under 500 KB, while a five-page scanned contract can be 30 MB because every page is a full-resolution photograph.

What compression actually does

PDFQuick's compressor renders each page at a chosen resolution and re-encodes it as a JPEG, then rebuilds the PDF from those images. That reliably shrinks image-heavy and scanned documents. The trade-off is real and worth stating plainly: the output is a picture of your page, so selectable text and links are lost.

Choosing a level

• Basic — light quality loss, good for documents you still want to read closely on screen.
• Recommended — the balance most email attachments need.
• Maximum — smallest file, visibly softer text. Use it for reference copies, not for print.

When to keep the original

If a PDF is already text-only and well optimised, rasterising it will make it larger, not smaller. PDFQuick measures the real before and after size and tells you when that happens — in that case, keep the original. Other honest alternatives are splitting the document into parts, or sending a link instead of an attachment.

Never compress the only copy of a legal or archival document. Keep the original file and treat the compressed version as a distribution copy.