2026-06-05 · 7 min read
Compress PDFs and images without unreadable results
Reduce file size for email and portal uploads while keeping text and receipts legible.
Government portals, job applications, and expense systems often cap uploads at 5–10 MB. A phone scan of ten receipts can exceed that instantly. Compression trades quality for size — this guide explains when to compress PDFs vs images and how to avoid unreadable output.
Image-heavy PDF vs text-native PDF
PDFs exported from Word are mostly text and vector graphics — compressing them as JPEG pages often hurts little because there are no photos. Scanned PDFs are full-page images — compression dramatically shrinks them but can blur small text.
Identify your PDF type: try selecting text. No selection means image-heavy — compression helps size but requires visual proofreading after.
PDF Compress in the browser
Our PDF Compress tool rasterizes pages to JPEG at a configurable quality. Lower quality means smaller files and more artifacts. Start at medium quality, download, and zoom to 100% on critical pages before submitting.
Do not compress signed legal PDFs for archival — keep the original and compress only the copy you upload.
Image Compress before PDF assembly
If you are building a PDF from photos (Images to PDF), compress JPEGs first. A 12 MP phone photo may be 4 MB alone; compressing to 200 KB before PDF assembly keeps the final bundle under portal limits.
Receipts need readable amounts and dates — err on higher quality for financial docs.
Resolution and DPI guidelines
Screen reading needs roughly 150 DPI; printing forms may need 300 DPI. Phone document modes often output 200–300 DPI automatically. Downscaling huge images before PDF conversion saves time and memory on mobile browsers.
For ID scans required by HR, follow their published specs — some forbid compression that obscures security features.
Workflow: email-ready expense PDF
1) Photograph receipts with document scan mode. 2) Image Compress each if files are large. 3) Images to PDF in chronological order. 4) PDF Compress if still over limit. 5) Open PDF at 100% zoom and verify totals.
Chain tools locally — your receipts never upload to a conversion server during any step.
When not to compress
Do not compress signed legal PDFs for archival — keep the original and compress only copies for upload.
ID scans and documents with security features may fail verification if over-compressed — follow recipient specs.