Client Sent a 47MB PDF (Here's What I Did)

The email came in at 11 PM. "Here's the presentation for tomorrow's meeting. Can you upload it to the portal?"

The portal has a 10MB upload limit. The PDF was 47MB.

I've dealt with this enough times that I have a system now. Takes about five minutes.

Why PDFs Get So Big

Nine times out of ten, it's the images. Someone pastes a 4000x3000 photo straight from their phone into a slide deck, and PowerPoint happily embeds the full-resolution original.

A 30-slide deck with 15 photos? Each photo at 3MB? That's 45MB just in images, before any text or formatting.

Other culprits:

• Embedded fonts (especially when every slide uses a different font)
• Vector graphics that are way more complex than they need to be
• Duplicate resources that the PDF generator didn't deduplicate

The Quick Fix

If you just need to get under a size limit and don't care about print quality:

1. Split the PDF into individual pages
2. Compress the images on each page
3. Merge everything back together

This alone usually cuts file size by 60-70%. The images get recompressed, and any duplicate resources get cleaned up during the merge.

When You Need to Keep Quality

Sometimes "make it smaller" means "make it smaller but don't ruin the photos because we're printing this on a 6-foot banner."

Fair enough. In that case:

Check the target resolution. A PDF for on-screen viewing only needs 72-150 DPI. Print needs 300 DPI. If your images are at 600 DPI for a screen presentation, you're storing 4x more data than necessary.

Remove pages you don't need. That 47MB deck had 8 appendix slides nobody was going to look at. Removing them dropped the file to 32MB before any compression.

Flatten transparency. Complex layered graphics with transparency effects add size. Flattening them helps, though it makes future editing harder.

The Nuclear Option

If nothing else works and you really need a tiny file, convert each page to a compressed image and rebuild the PDF from those images.

You lose text selectability and searchability. But for a meeting presentation that people just need to see on screen? Nobody will notice.

Prevention Is Easier

If you're the one creating the PDF:

• Resize images before inserting. If a photo will display at 800px wide in the document, resize it to 800px first. Don't let the PDF software downscale a 4000px original internally.
• Use "Save as" instead of "Save." Some PDF editors accumulate deleted content. Save As creates a clean file.
• Choose "Minimum Size" export settings when your tool offers them.
• Link images instead of embedding when possible, then flatten at the end.

My Actual Workflow

Here's what I did with that 47MB file:

1. Opened it, removed the 8 appendix pages → 32MB
2. Split into individual pages
3. Compressed each page's images at 85% quality
4. Merged back together → 8.4MB
5. Uploaded to the portal with room to spare

Total time: about 4 minutes. The client never knew there was a problem.

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Big PDFs are one of those problems that seem annoying until you have a workflow. Then it's just five minutes and done. Keep these tools bookmarked — you'll need them more often than you think.