Most scanning apps default to one format and leave it there, which works fine for typical text pages but is not actually the best choice for every kind of document. Picking the right format for what is actually on the page — text, a photo, a mix of both — makes a real difference to both file size and how the final document looks.
JPG: the default for most scanned pages
JPG is the right choice for the majority of scans — letters, forms, printed pages, anything that is mostly text with maybe a logo or a small amount of colour. It compresses efficiently, producing small files, and the slight softening it introduces is not noticeable on typical printed text at normal reading size. If your scanning app defaults to JPG, that default is correct for most everyday documents.
PNG: for specific cases where JPG falls short
- Documents with fine, small text where JPG’s slight softening becomes noticeable — a densely printed legal document with tiny footnotes, for example.
- Pages with sharp lines, diagrams or technical drawings where JPG can introduce faint fuzzing around hard edges.
- Anything that needs to stay perfectly crisp even after several rounds of editing, since PNG does not lose additional quality each time it is re-saved the way JPG can.
The trade-off is size — PNG files are typically several times larger than an equivalent JPG, so use it selectively rather than as a default for every scan.
Steps to convert if you picked the wrong one
- If a scan already exists in the wrong format, use the relevant converter — PNG to JPG to shrink an oversized document scan, or the reverse if you specifically need PNG’s crispness for a technical page.
- Check the converted result at normal reading size to confirm text is still comfortably legible.
- If the file needs to be smaller still, run it through the Image Compressor after converting.
What about PDF as the “format” itself?
For a multi-page document, neither JPG nor PNG is really the end format you want to share — a PDF containing the pages, built with Image to PDF, is the more practical container regardless of which image format you scanned into. The PDF wraps around JPG or PNG images internally, so the format choice for each individual page still matters for the final file size, even once everything is combined into one document.
A quick decision guide
- Plain text letter, form, or printed page — JPG.
- Technical diagram, fine print, or a document you will edit repeatedly — PNG.
- A scanned photograph within a page (an ID photo, an old print) — JPG, since it is genuinely photographic content.
- A logo or line-art graphic within the page — PNG, or better still SVG if you need it standalone and scalable.
Frequently asked questions
Does the format choice matter if I am going to compress the file anyway?
Yes — starting from the right format still gives a better result after compression than starting from the wrong one and compressing harder to compensate.
Is there a format better than both JPG and PNG for scans?
WebP can offer a good balance of small size and sharp detail and is worth trying if your workflow supports it, though JPG remains the most universally compatible choice.
Can I mix formats within the same multi-page document?
Yes — each page can be scanned or saved in whichever format suits its content, and combined together into one PDF regardless.
Does scanning in colour vs black-and-white affect which format is best?
Not the choice between JPG and PNG directly, but scanning in greyscale or black-and-white when the document has no meaningful colour reduces file size significantly on top of any format choice.
Is converting between formats free?
Yes. No sign-up, no watermark, and files are removed from the server automatically about an hour after processing.