JPG vs PNG: Which Should You Use? (A Practical Guide)

JPG vs PNG has one reliable answer that covers almost every real decision: photographs go to JPG, everything with sharp edges goes to PNG. The rest of this explains why, and covers the cases where the rule needs thinking about.

The one-line rule

• Photographs, camera images, anything with soft gradients → JPG
• Screenshots, diagrams, logos, charts, text, line art, anything needing transparency → PNG

If you stop reading here you will make the right call roughly 95% of the time.

What actually differs

JPG is lossy. It analyses the image and throws away detail the eye is unlikely to notice, particularly fine colour variation. On a photograph this is remarkably effective — you can discard most of the data and see no difference. On a sharp black-on-white edge it is bad, because the algorithm smears the transition and leaves visible fringing.

PNG is lossless. Every pixel is stored exactly. Crisp edges stay crisp forever. The cost is size: a photograph saved as PNG can be five to ten times larger than the JPG, for a difference you cannot see.

Two more differences that decide cases on their own:

• Transparency. PNG has a full alpha channel; JPG has none. If any part of the image must be see-through, the decision is made.
• Generational loss. Every JPG save re-compresses. Open, edit, save, repeat, and it visibly degrades. PNG survives unlimited re-saves untouched, which makes it the better working format even for images that will eventually ship as JPG.

Why screenshots must be PNG

This is the mistake worth naming, because it is the most common one.

A screenshot is mostly flat colour with hard-edged text. That is precisely JPEG's worst case. Save a screenshot as JPG and you get grey speckling around every letter and a faint halo along every window border. It looks cheap, it is harder to read, and the file is often larger than the PNG would have been — because the compression is fighting content it was never designed for.

Screenshots, UI captures, code samples, charts with labels: PNG, every time.

Converting a PDF to images

This is where the choice comes up most in document work, and the same rule holds with one adjustment.

When you convert a PDF to PNG, you are rendering pages that usually contain text, tables and rules — all sharp-edged. PNG is the default for document pages and the reason that conversion is named for it.

Choose JPG only when the page is essentially a full-page photograph, where the size saving is real and the artefacts have nothing sharp to attack.

Resolution matters more than the format here. A page rendered at low DPI looks poor in either format; raise the DPI for print or for cropping a detail out of a page, and accept the larger file.

Going the other way

Building a PDF from images is the reverse trip, and format matters less because the image is embedded rather than re-compressed:

• PNG to PDF — screenshots and scans. Note that PDF pages have no alpha, so transparent areas composite onto white.
• JPG to PDF — photographs. The existing JPEG data is embedded as-is, so there is no second lossy pass.

Both are lossless with respect to what you started with. The choice was made when the image was created, not when it goes into the PDF.

What about WebP, HEIC and the rest?

Briefly, because they come up:

• WebP — smaller than both at similar quality, with transparency, and now broadly supported in browsers. Still patchy in desktop software and print workflows, so excellent for the web and awkward for handing to other people.
• HEIC — what iPhones produce. Roughly half a JPG's size, and poorly supported outside Apple's ecosystem.
• TIFF — lossless, huge, and still standard in print and archival work.

None of these displaces the basic rule. JPG and PNG remain the two formats you can send anyone without thinking.

Doing it on your own machine

The PDF Converter renders PDF pages to PNG or JPG at whatever resolution you choose, and the Office Converter moves between image formats — all locally, with no upload, no file-size cap and no watermark.

A note on why this is free

BizTray shares a portion of your spare internet bandwidth through a vetted partner rather than charging you. It relays other parties' web traffic and never touches your files. Sharing is switchable off from Settings or the tray, and the tools do not run while it is off. See How it's funded.

Related

• PDF to PNG — where this choice comes up most.
• PNG to PDF — the reverse trip.
• What is a HEIC file? — the format your phone is using instead.