PNG vs JPG: Which Format Should You Use?

PNG and JPG are the two formats you'll meet most often, and choosing between them is less about which is "better" and more about what your image actually is. One is built for pixel-perfect graphics with transparency. The other is built for photographs that need to stay small. Get the match right and your images look great and load fast. Get it wrong and you either blur your text or bloat your page.

The one-line rule

• Use PNG for logos, icons, screenshots of text, line art, and anything that needs a transparent background.
• Use JPG for photographs, complex imagery with lots of colour gradients, and any large graphic where file size matters more than perfect edges.

That covers most decisions. The rest of this post is about why, and what to do when the answer isn't obvious.

How the two formats actually differ

The difference comes down to how each one stores pixels.

PNG is lossless. It records every pixel exactly, which is why a screenshot of black text on white stays razor-sharp. It also supports an alpha channel, so parts of the image can be fully or partially transparent. The cost is size: storing everything faithfully takes a lot of bytes, especially for photos.

JPG is lossy. It throws away detail your eye is least likely to notice, then compresses what's left. That makes it tiny compared to PNG for photographic content: often five to ten times smaller. The trade-offs are that it can't do transparency, and pushing compression too far introduces visible "artifacts," particularly around hard edges and text.

When PNG is the right call

Reach for PNG when edges and transparency matter:

• A company logo that needs to sit on different coloured backgrounds.
• UI mockups and screenshots where crisp text is essential.
• Icons, diagrams, charts, and flat-colour illustrations.
• Any image you'll edit repeatedly, since lossless means no quality decays with each save.

If you compress a screenshot of text as JPG, you'll see fuzzy halos around every letter. That's the format warning you it's the wrong tool.

When JPG wins

Reach for JPG when size matters and the image is photographic:

• Photos on a blog, product page, or gallery.
• Large exports and screen captures that are needlessly heavy as PNG.
• Email attachments and uploads where a smaller file simply works better.

A detailed PNG photo that weighs 4 MB can often become a 400 KB JPG that looks identical on screen. That's the difference between a page that feels instant and one that stalls.

The awkward middle: transparent PNGs you want smaller

The tricky case is a large PNG that has transparency but is really a photo or screenshot. You want JPG's small size, but JPG can't keep the transparent areas. The fix is to flatten the image onto a solid background colour first, then encode as JPG.

That's exactly what our PNG to JPG converter does: you pick the fill colour that replaces the transparent pixels (white for documents, black for dark UIs, or any custom hex) set the quality, and download a much smaller JPG. It all runs in your browser, so nothing is uploaded.

A quick decision checklist

Ask yourself, in order:

1. Does it need transparency? If yes, keep it as PNG (or flatten it deliberately for JPG).
2. Is it text, a logo, or line art? If yes, PNG keeps it crisp.
3. Is it a photo, or just too big? If yes, JPG will be dramatically smaller.
4. Will I re-edit it many times? If yes, PNG avoids repeated quality loss.

Name what your image is

Neither format is universally superior, they're specialists. PNG protects sharp edges and transparency. JPG delivers small, fast photographs. Once you can name what your image is, the right format picks itself. And when you have a heavy PNG that would be happier as a JPG, converting takes seconds.

A note on how our converter treats each

Conversions here run through Squoosh's WebAssembly codecs in your browser: MozJPEG when the destination is JPG, and a PNG encode followed by OxiPNG's lossless optimiser when the destination is PNG. The practical meaning: converting to PNG never invents quality that a JPG already discarded, and converting to JPG makes its quality decision once, with a dial you control. Neither direction uploads anything.

Sources

• Image file type and format guide (MDN Web Docs)
• PNG Specification (Third Edition) (W3C)