PNG vs JPG — When to Use Each (And What Not to Believe)

There is one question that decides this, and most explanations bury it under a comparison table.

Is the image a photograph, or is it a graphic?

Photographs are continuous tone — colours shift gradually, there are no perfectly flat areas, no hard edges. Graphics are the opposite: logos, screenshots, charts, text, line art, anything with large blocks of identical colour and crisp boundaries.

Photograph, use JPG. Graphic, use PNG. That covers the vast majority of decisions, and everything below is why.

Why the split works

The two formats compress in fundamentally different ways.

JPEG was designed for photographs. It discards detail your eye is unlikely to notice, and its assumptions are built around smooth tonal variation. Give it a photo and it produces a small file that looks identical. Give it text or a logo and it produces visible ripples around every edge, because a hard boundary is exactly the fine detail it is trying to throw away.

PNG is lossless — every pixel comes back exactly as stored. Its compression looks for repeated patterns, which flat colour provides in abundance. A screenshot of a settings page compresses beautifully. A photograph of a forest does not, because almost no two adjacent pixels are the same, so a PNG of a photo is often five to ten times larger than the JPEG.

So it is not that one format is better. Each is efficient at what the other is bad at.

Three things people get wrong

These come up constantly, including in articles from large, reputable sites.

"PNG is higher quality." PNG is lossless, which is not the same thing. Lossless means it faithfully preserves whatever it was given. A PNG made from a badly compressed JPEG preserves the damage perfectly. The format does not improve anything; it only stops further loss.

"Convert your JPGs to PNG to improve them." This does nothing except make the file larger. The detail JPEG discarded is gone from the data. Saving it as PNG stores the remaining pixels more faithfully — and those pixels already include every artefact. You get a file three times the size that looks identical.

The one time this is worth doing is before an editing session. If you are going to make several rounds of edits, working in PNG stops each save from compounding the loss, and you export to JPEG once at the end.

"PNG supports higher DPI, so it is better for print." DPI is a number in the file's metadata that describes intended print size. Both formats store it, and it has nothing to do with image quality — what DPI actually means is one of the most misunderstood things in this whole subject.

For print, the relevant difference is the opposite of what that claim suggests: JPEG can be saved in CMYK, the colour model printers use, and PNG cannot. PNG is RGB only. Plenty of commercial print workflows will reject a PNG for exactly this reason.

The genuine differences

Transparency. PNG has an alpha channel. JPEG has none at all. Save a transparent image as JPG and every transparent pixel becomes a solid colour, usually white. This is irreversible, and it is why a logo suddenly has a white box around it. If transparency matters, the decision is made for you.

File size on photographs. JPEG wins decisively, usually by a very large margin.

File size on flat graphics. PNG often wins, and looks better while doing it. A screenshot saved as JPEG can be both larger and visibly worse than the same screenshot as PNG.

Editing. PNG survives repeated saves. JPEG degrades a little every time, and the losses accumulate.

Colour model. JPEG supports CMYK for print. PNG is RGB only.

Practical cases

Photographs anywhere — JPG. Quality 80 or so, which is invisible for most pictures.

Screenshots — PNG, always. This is the single most common mistake. Screenshots are made of text and interface edges, exactly what JPEG handles worst, and the JPEG version is frequently the larger file too.

Logos and icons — PNG, for the transparency and the crisp edges. Better still, SVG if you have it, since that scales to any size.

Anything with text in it — PNG. Charts, diagrams, infographics, receipts.

Photos with a transparent background — PNG, and accept the size. There is no other option among these two.

Print — JPEG at high quality, in CMYK if the printer asks for it. Check what they want rather than guessing.

The modern answer for websites

If the image is going on a web page, both of these are the old choice.

WebP handles both cases better: it does lossy compression for photographs at roughly 25 to 35 percent smaller than JPEG, lossless compression for graphics, and it supports transparency in both modes. Every current browser reads it.

AVIF compresses better still, though support outside browsers is thinner.

The reason to stay with JPG and PNG is compatibility with things that are not browsers — upload forms, print services, older software, colleagues on old machines. That is a real constraint, and it is why these two formats are not going anywhere.

Getting the size down

Whichever you choose, most of the file size comes from pixel count rather than format. A 4000-pixel-wide photo displayed at 800 pixels is wasting most of its data no matter how you save it.

Resize first with the resizer, then compress at a quality you have actually looked at. For PNGs, reducing the dimensions is usually the only lever you have, since there is no quality slider.

The short version

Photographs go to JPG; graphics, screenshots and anything needing transparency go to PNG. PNG is lossless, not magically higher quality, and converting a JPEG to PNG improves nothing while tripling the file size. For print, JPEG is the one that handles CMYK. And for a website, WebP is better than either — keep JPG and PNG for the places that will not accept anything else.