Shrink PDFs before emailing without losing readability
Tomoda HinataTool author & maintainerPublished Apr 18, 2026Updated Apr 26, 20269 min read
A 20-page PDF full of photos easily hits 15–30 MB. Most corporate email gateways reject anything over 10 MB. The compact recipe: right-size every photo BEFORE building the PDF, prefer JPG over PNG for page photos, never rasterize text, and strip metadata at the end. A 25 MB PDF lands at 4 MB with no visible quality loss.
Tools used in this guide
Why is PDF compression so bad on its own?
PDF wraps existing assets — it does not run a heavy codec on what is already inside. The compression effective at the PDF level is mostly Flate (zlib) on streams; Flate is excellent on text and vector data, very mediocre on photos. Every byte gain therefore needs to come from the assets BEFORE they enter the PDF, not from the PDF itself.
Right-sizing photos first
Resize each photo to 1600 px on the long edge and re-encode as JPG quality 80 before adding to the PDF. A 12 MP iPhone photo (4032×3024, ~3.5 MB JPG at quality 100) drops to ~250 KB at 1600/Q80 — a 14× reduction with no perceivable difference in the printed PDF.
JPG vs PNG for page photos
PNG embeds losslessly which is great for logos and screenshots with text but disastrous for photos: a continuous-tone PNG is roughly 5× the byte count of an equivalent JPG. Use JPG for photos, PNG only for graphics that need transparency or pixel-perfect text edges.
Why not rasterize the text?
Some 'optimize for size' workflows rasterize entire pages — flattening text to images. This destroys accessibility (screen readers, copy-paste, OCR), kills search indexing, and disables form fields. Keep the text layer. The size win from rasterization is rarely worth the irreversible loss.
Stripping PDF metadata
PDFs accumulate metadata across edits: the author, comments, deleted revision history, software fingerprints, sometimes file paths. A final metadata cleanup typically drops 2–10% of the size and removes information your recipient does not need (and sometimes should not have). The EXIF/metadata cleaner handles PDFs as well as images.
Steps
About 5 minExtract and resize photos
Pull every photo from the PDF, resize to 1600 px long edge, re-encode at JPG quality 80.
Rebuild the PDF
Use the image-to-PDF tool to assemble the resized photos into a new PDF, keeping the original text layer if present.
Strip metadata
Run the EXIF/metadata cleaner on the resulting PDF to remove author and revision history.
Verify the size
Check the final file size in your file manager — a 25 MB PDF should land at 3–5 MB.
Frequently asked questions
What is a safe target size for business PDFs?
Aim for under 5 MB. Most corporate gateways accept up to 10 MB, but 5 MB leaves headroom for the recipient's own send-as-attachment forwarding.
Will Acrobat's 'Reduce File Size' do the same job?
Partly. Acrobat re-encodes embedded images, but cannot recover from already-bloated PNGs without quality loss. Pre-shrinking the assets gives a tighter result with full control over the trade-off.
Does compressing the PDF break form fields?
Image-level recompression and metadata stripping leave form fields intact. Rasterization (which we recommend against) breaks them.
What about scanned PDFs?
Scans are essentially PDFs of images. Apply the same recipe: resize to 1600 px, re-encode as JPG quality 80. For text-heavy scans, run OCR first so the resulting PDF still has a searchable text layer.
Is the process private?
Yes — every step happens in your browser. The PDF is never uploaded.
Try it now
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