What file size should I aim for?

Aim for the smallest size that passes the platform check while remaining readable. For most portals, 1–10 MB is typical; for email, 5–20 MB is common; and for forms with strict limits, 500 KB–2 MB may be required.

Will compression ruin text in screenshots and diagrams?

It can if you compress as a low-quality JPG. For screenshots, use moderate JPG quality with sharpening disabled, or PNG for sharp edges when size permits. Always preview at 100% before uploading.

Why does my PDF get bigger after I edit it?

Many editors embed new resources (fonts, duplicated images, incremental save layers). A final optimisation pass and removing unused objects often restores a smaller file.

Is it better to split or compress?

Compress first if quality can be preserved. Split when the target limit is extremely low, when a portal rejects certain content types, or when you need separate uploads for different document categories.

Do online tools keep my files?

Policies vary. For sensitive files, avoid uploading personal documents to untrusted services, remove metadata, and consider local workflows when possible.

What’s the difference between DPI and quality?

DPI is resolution for print and scan; quality is the compression strength. A 300 DPI scan can still look poor if quality is too low. Conversely, 150–200 DPI at a reasonable quality can remain very readable.

Can I compress without losing text search?

Yes. If the PDF contains real text (not just images), keep it as text and only compress embedded images. If it is scanned, consider OCR to add searchable text while optimising the images.

What should I do if the portal still rejects my file?

Re-check allowed formats, remove passwords, flatten forms if required, ensure page count limits are met, and try exporting to PDF/A or standard PDF if the portal has strict validators.

PNG Transparency vs File Size: When to Use PNG and When to Switch to JPG

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You upload a file at the last minute and the portal rejects it with a blunt message: “File too large.” In practice, the fastest wins come from fixing the source first, then doing one clean optimisation pass (not five repeated re-saves).

In this image guide—PNG Transparency vs File Size: When to Use PNG and When to Switch to JPG—you’ll learn what makes files large, which changes deliver the biggest savings, and how to keep the result readable and portal-friendly. Below is a straightforward workflow you can repeat.

When you’re ready, use Image tools (and the related tools listed below). The approach is: clean first → optimise once → verify.

JPG vs PNG: pick based on what’s inside the image

JPG is ideal for photos and scans. PNG is ideal for sharp graphics and transparency. Choosing the right format is often a bigger win than “more compression.”

Workflow

Crop with Image Cropper.
Use JPG for photos/scans; PNG for logos/transparency.
Compress and verify at 100% zoom.

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Quick tool path:

If you’re in a hurry

Split the file instead of destroying quality.
Keep scanned pages grayscale when colour isn’t required.
Resize photos before embedding them in documents.
Do a quick test upload if the portal allows it.

Most “stuck” cases are solved by the first two steps. Once the file is structurally clean, optimisation becomes predictable.

Quality check before you hit “Submit”

A 30‑second check beats a 30‑minute fix after the deadline.

Open at 100% zoom and check the smallest text (names, dates, serial numbers).
Scroll every page for rotation, missing pages, and blank pages created by exports.
Confirm file size against the true limit (some portals count after upload).
Test on mobile if the recipient opens it on a phone.
Do a test upload if possible; validators can reject encryption or unusual PDF structures.

Troubleshooting by error message

Use the error text as a clue. The fix for “too large” is different from “can’t be processed.”

“File too large”: Reduce size by removing pages, resizing images, or splitting. Start with Split PDF if the limit is strict.
“File can’t be processed / invalid”: Re-export a clean copy and avoid encryption. A single clean pass via PDF tools often resolves validator errors.
“Upload failed” (but size is ok): try smaller parts or a lighter file (timeouts are common).
“Security settings / password protected”: portals often reject encrypted files—use an unencrypted export.

Real-world examples (what “good” looks like)

If you’re far outside these ranges, it usually means oversized images or repeated export layers.

1–3 page form: commonly under 500KB–2MB (depends on scans/photos).
10–20 page text report: often 1–5MB when exported cleanly and images optimised.
Scanned pages: biggest wins come from grayscale + sensible DPI (~150–200).

On mobile: what changes

On mobile, the fastest win is usually resizing images (not just compressing). A smaller pixel dimension uploads faster and stays readable.

Common mistakes

Leaving comments/annotations when the portal expects a clean file.
Embedding videos in slides when a link would do.
Keeping full‑colour scans when grayscale is acceptable.
Repeated re-saving that adds incremental-save history and duplicate resources.
Pasting huge screenshots/photos (4000–8000px) when 1500–2500px is enough.
Compressing five times in a row instead of doing one clean export.
Using PNG for photos when JPG would be much smaller.

FAQ

What should I do on mobile?

Do the final check on the same device you’ll submit from. Mobile viewers can reveal issues (blurry text, missing fonts) you won’t notice on desktop.

Why did the file get bigger after editing?

Some editors add incremental-save history and duplicated resources. A clean export + one optimisation pass usually fixes it.

Is it safe for private documents?

Prefer tools that process locally in the browser and keep a clean local copy. For highly sensitive files, avoid unknown uploaders.

How do I get even smaller without blur?

Prefer splitting, grayscale for scans, and resizing images before export. Extreme compression is what creates blur.

Why does my image look blurry?

Either it was resized too small or JPEG quality was set too low. Keep a sensible pixel size and check text at 100% zoom.

Related guides you can use next

Final takeaways

For most submissions, the winning pattern is consistent: clean first → optimise once → verify. That keeps quality high and reduces portal errors.

Next step: run Image tools and use the checklist above before you upload or send.