PDF compression changes little? Check structure versus scanned images

What this mode actually changes

pdf-lib SaveOptions includes useObjectStreams. KitNelo enables it when saving the document again. The current implementation does not re-encode or shrink embedded images in this mode, so structure compression should not be read as a scan-image quality control.

An image-heavy or already well-compressed PDF may change little or become larger. A completion message is not evidence that an upload limit has been met. Compare the downloaded file properties rather than relying on a rounded percentage. No fixed reduction or target size is promised.

Keep the original and define the requirement

Use a PDF copy that opens normally. Record its original size and page count, plus the receiving limit. Decide whether every page is needed. If only part of the document is being delivered, follow the PDF page extraction guide to define that range first.

Inspect representative pages for selectable text, full-page photos and fine table lines. These observations help choose the next method; text that cannot be copied does not alone prove corruption. Follow the searchable scanned PDF guide when a text layer is needed.

Re-save in the PDF workspace

1. 1Open the PDF workspace and select Compress PDF structure.
2. 2Add the PDF and confirm the active file and mode. This mode processes one PDF at a time; check the selected item if several files are present.
3. 3Run processing and wait for the automatic download with a filename ending in -compressed.pdf. Do not submit solely because a success message appeared.
4. 4Compare original and output bytes in the same file manager, then open the output to check page count and important pages.

There is no scan-resolution, compression-quality or target-size slider in this mode.

A smaller file is only one acceptance check

Editorial suggestion: record original bytes, output bytes, matching page count, readable key content and the receiver result. This is a reporting template, not a claim that your file has already been tested.

• Scope: match the selected document page count and inspect the first, last and representative middle pages.
• Content: zoom into small text, table lines and pictures. Check that originally selectable text can still be selected.
• Size: compare bytes or identical units. Choose another method if the output grows, does not shrink or still exceeds the receiving limit.
• Delivery: open it in the intended reader. Separately verify special forms, signatures and interactive content; page appearance alone is insufficient.

What to do if size does not improve

Reduce the delivered page range when that meets the requirement. If scanned images dominate the size, adjust resolution and quality at the scan source or use a tool designed to re-encode images, then check text clarity. Rendering every page to an image and assembling it again is not a general fix; it may remove the text layer and increase size.

This mode processes files in the browser and remains limited by memory and parseability. Password protection, damage or unusual structures can cause failure. Keep the original. Re-saving is not privacy removal, universal PDF repair or digital-signature verification.