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⚖️ PDF vs JPG vs PNG: Which Format Should You Use?

By the MZScan team · Updated 17 October 2026 · 3 min read

PDF, JPG and PNG are the three formats you will meet most often when you scan documents, upload forms or share files. They are not interchangeable. Each one is good at something and poor at something else, and choosing the wrong one is a common reason for blurry text, huge files or a rejected upload.

The short answer

• PDF for documents with one or more pages that must keep their layout: applications, contracts, reports, anything that will be printed or sent as one file.
• JPG for photos and for uploads with a strict file-size limit.
• PNG for screenshots, text-heavy images, logos and anything that needs a transparent background or very sharp edges.

What each format is

JPG (or JPEG) is a lossy image format. It makes files small by discarding detail that the eye barely notices. It is excellent for photographs, but it blurs fine lines and can leave faint blocky marks around text. It does not support transparency, and saving a JPG again and again slowly lowers its quality.

PNG is a lossless image format. Nothing is thrown away, so edges and text stay crisp, and it supports transparent backgrounds. The price is size: a photo saved as PNG is usually much larger than the same photo as JPG.

PDF is a document container, not just an image. It can hold many pages, keeps the page size and layout fixed, and can contain images, text and fonts. A scanned PDF is usually a set of page images placed inside that container.

Which one for which job

• Online forms that ask for a photo or ID copy: JPG, kept under the size limit. See how to compress an image to 20, 50 or 100 KB.
• Job or admission applications: one PDF, combining your documents in the order requested. See how to merge PDF files.
• A signature to place on documents: PNG with a transparent background.
• Screenshots and text on images: PNG, because JPG blurs small text.
• Sharing one page in a chat: JPG or PNG. See how to turn PDF pages into images.
• Printing: PDF, so the page size and margins stay correct.

File size and quality

For a photo, JPG is usually the smallest. For a page of text, the difference is smaller and PNG often looks better, so choose by what matters more: size or sharpness. A PDF is as big as the images inside it, so reducing the images before you build the PDF is the most effective way to get a smaller file.

Common mistakes

• Saving a photograph as PNG for an upload with a small size limit.
• Converting a JPG to PNG and expecting better quality. A JPG that is already blurry does not become sharper by changing its format.
• Sending several separate image files when the receiver asked for one PDF.
• Compressing the same JPG repeatedly. Always start again from the original photo.

How to convert between them on MZScan

Use Image to PDF to turn pictures into a PDF, PDF to Image to turn PDF pages into JPG or PNG, the scanner to save a cleaned page as PNG, JPG or PDF, and the compressor to bring an image down to a size limit. All of them run in your browser.

Frequently asked questions

Is PDF better than JPG for documents?
For multi-page documents and printing, yes. For a single photo-like upload with a size limit, JPG is often the better choice.

Why is my PNG so large?
PNG keeps every detail, so photos become large. Use JPG for photos unless you need transparency or perfectly sharp edges.

Can I turn a scanned PDF back into editable text?
Not by changing the format. The editor can detect text on a scanned page so you can change it, but the page is saved as a picture after editing. See the editing guide.

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