How to Convert PNG to JPG on Mac

Convert PNG images to JPG on a Mac with Kompressor, the Finder Quick Action, Preview or the Terminal. In our test, 30 PNG files became 77% smaller as JPG.

Steps

Download Kompressor for Mac or get it on the Mac App Store
Open the Kompressor app
Drag and drop your PNG image(s) into Kompressor
Select JPEG as your output format
Adjust compression settings as needed
Click on the ▷ (play) button to convert your PNG image(s) offline

Kompressor is free to try: you get 3 conversions, and each conversion can include as many images as you want.

Should you convert PNG to JPG?

PNG is lossless and makes large files. JPG is lossy, makes much smaller files and opens everywhere. For photos that were saved as PNG, a conversion to JPG saves a lot of space with almost no visible change.

Do not convert these images to JPG:

Images with transparency. JPG does not support transparency, so transparent areas get a solid background.
Screenshots, logos and text. JPG compression makes sharp edges and small text soft. Keep these as PNG, or use WebP.

How much smaller is JPG? Our test

We converted 30 PNG files (48.7 MB in total) to JPEG at the default quality of 80%. The JPEG files had a total size of 11.1 MB, which is 77% smaller. The result depends very much on the image: the median file became 77% smaller, but one file became only 4% smaller. For comparison, the same files as WebP at 80% had a total size of 3.6 MB.

Tested in November 2026 with the conversion engine of Kompressor on a MacBook Pro (M3 Max, 14 cores) with macOS 27. Your results depend on the images.

Other ways to convert PNG to JPG on Mac

Finder Quick Action

Select the images in Finder, right-click and choose Quick Actions > Convert Image. Select JPEG and a size. This is the fastest built-in method. It offers only JPEG, PNG and HEIF, and it has no quality control.

Preview

Select the images in Finder and open them with Preview. They open in one window.
Click a thumbnail in the sidebar and press ⌘A to select all.
Choose File > Export Selected Images, click Options and select JPEG.

Preview is free and already on your Mac. It applies one setting to all images without a preview of the result.

Terminal (sips)

sips is part of macOS and converts a whole folder with one command:

mkdir converted
sips -s format jpeg -s formatOptions 80 *.png --out converted

The number after formatOptions is the quality from 0 to 100. There is no preview, so you must open the results to check them.

When Kompressor is the better tool

Kompressor shows the JPG result next to the PNG original with the real file size before you convert. This shows you at once if an image is a bad candidate for JPG. It also converts whole folders and can resize the images in the same step.

Which quality setting to use

Kompressor shows quality as a bar with ten steps, from 10% to 100%. The default is 80%, and it is a good start for photos. Before you convert, open the compare view: drag the slider across the image to see the original next to the result, with the real output file size. Lower the quality until you see a difference, then go one step back.