Images
PNG vs JPG: Which to Use, With Measured Sizes
Use JPG for photographs and PNG for screenshots, logos, text and anything with transparency. JPG throws away detail to get small files. PNG keeps every pixel exactly, so photos saved as PNG are many times larger. We measured the same photo both ways below.
How much bigger is a PNG than a JPG?
We cropped one image to 2000 × 1500 and saved it as PNG and as JPG at several qualities with sips. The source is a smooth rendered image, so a camera photo with fine noise gives bigger files in both formats.
| Format | File size |
|---|---|
| PNG | 2.4 MB |
| JPG quality 100 | 1.7 MB |
| JPG quality 90 | 255 KB |
| JPG quality 80 | 169 KB |
| JPG quality 60 | 117 KB |
At quality 80 the JPG was about one fourteenth of the PNG. Now the opposite case: a 1600 × 900 flat graphic (solid shapes plus a line of text):
| Format | File size |
|---|---|
| PNG | 53 KB |
| JPG quality 95 | 61 KB |
| JPG quality 80 | 54 KB |
Here PNG was no bigger than the JPG, and the JPG still added blur around hard edges. That is the whole rule: photos favor JPG, flat graphics favor PNG.
When should I use PNG and when JPG?
| Your image | Use | Why |
|---|---|---|
| Photograph | JPG | Smooth tones and noise compress well in JPG. PNG wastes bytes. |
| Screenshot with text | PNG | Sharp edges stay sharp. See the note on screenshots below. |
| Logo or icon | PNG | Flat color and crisp edges, often with transparency. |
| Needs transparent background | PNG | JPG has no transparency channel. |
| Chart or diagram | PNG | Lines and text suffer visible artifacts in JPG. |
| Image you will edit again and again | PNG | No generation loss on each save. |
| Photo for email or a web page | JPG | Smaller and universally supported. |
Screenshots that are mostly UI and text are the one case where PNG wins. A screenshot of a photo-heavy page can be large as PNG. To turn a big PNG screenshot into a JPG copy, see how to convert PNG to JPG on a Mac.
Is PNG higher quality than JPG?
PNG is lossless: what you save is exactly what you get back. JPG is lossy: it discards detail the eye is least likely to miss, and the loss grows as you lower the quality setting or re-save the file. At quality 90 and above, most people cannot tell a JPG photo from its PNG source on screen.
But a PNG made from a JPG is not better than that JPG. Converting JPG to PNG makes the file bigger and cannot restore lost detail. See how to convert JPG to PNG on a Mac for the reasons people still do it (transparency edits, a site that demands PNG).
How do I convert between PNG and JPG on a Mac?
In Preview, open the image and choose File > Export, pick JPEG or PNG, and use the quality slider for JPEG. In Terminal:
sips -s format jpeg -s formatOptions 80 image.png --out image.jpgTransparent areas become a solid background when you go to JPG, because JPG cannot store transparency. Check the result.
Is there anything better than PNG or JPG for the web?
Yes, for web pages: WebP and AVIF usually beat both at the same visual quality, and WebP can carry transparency, so it replaces PNG for many web graphics. The catch is compatibility. JPG and PNG open everywhere, including email clients, office apps and upload forms, while newer formats do not always.
To switch a PNG, see how to convert PNG to WebP on a Mac. If a site or app refuses an AVIF file you were sent, converting AVIF to JPG fixes it. For where each format fits on a site, see image compression for web.
Does re-saving a JPG make it worse?
Yes, a little each time, because each save re-applies lossy compression to an already compressed image. One save at a sensible quality is fine. Five rounds of edit and export is how a photo ends up blotchy. Keep the original or a PNG master, and export JPG once, at the end.
Quality settings are not comparable across tools, so do not copy a number from one app into another. Judge by eye on a zoomed-in crop, and stop at the lowest quality that looks the same.
When is Smol the wrong tool for this?
One image, once: Preview or sips is free and enough. If you need a PNG kept pixel-for-pixel smaller, Smol is the wrong tool, because it has no lossless mode and always re-encodes. ImageOptim is the free answer for that.
Smol earns its $29 (one Mac, paid once) on batches and mixed folders, from the Finder right-click, with nothing uploaded. On the 24 small (768 × 512) test photographs on the benchmark page, its default settings made JPEGs 69.3% smaller and PNGs 69.2% smaller, and compressing the PNGs to AVIF at quality 65 saved 92.1%. Those are results on those images, not a promise for yours. See the best image compressor for Mac roundup or pricing.
How we checked this
Saved one 2000x1500 crop and one flat 1600x900 graphic as PNG and as JPG at several qualities with sips on a Mac and read the sizes. Smol figures come from the published benchmark. Facts last checked . We make Smol, so treat our claims about it with the same care as any vendor’s, and see our editorial policy.
PNG vs JPG: common questions
Is PNG or JPG better for photos?
JPG, in almost every case. Photos have smooth gradients and fine noise that JPG compresses well. In our test, a 2000 × 1500 photo was 2.4 MB as PNG and 169 KB as JPG at quality 80, with no difference most people could see on screen.
Does PNG lose quality like JPG?
No. PNG is lossless, so saving it again never degrades it. JPG is lossy, and each re-save at a lower quality can add artifacts. If you edit an image repeatedly, keep a PNG or the original and export JPG only at the end.
Why are my screenshots PNG and so large?
macOS saves screenshots as PNG by default because they usually contain sharp text and interface edges. A screenshot with photos in it gets large. If the content is mostly photographic, converting a copy to JPG makes it much smaller.
When should I use PNG instead of JPG?
Use PNG for logos, icons, charts, screenshots of text, and anything with a transparent background. JPG has no transparency and adds blur around hard edges, so those images look worse as JPG and often are not smaller.
Will converting PNG to JPG reduce file size?
Usually, for photographs, by a large margin. For flat graphics the saving can be small or zero, as our 1600 × 900 test graphic showed. Transparency is lost and edges can blur, so check the result before replacing anything.
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