The fastest way to convert PNG to JPG on Mac

The simplest method is to use the Preview app that comes built into every Mac. Open your PNG file in Preview, click File in the menu bar, select Export As, change the format dropdown from PNG to JPEG, choose where to save it, and click Save. The file converts when ready and you now have a JPG version alongside your original PNG.

This works for single files or batches. If you have many PNGs to convert, you can repeat the process for each one, or use Automator (also built in) to convert a whole folder at once without opening each file individually.

Key Takeaways

  • Preview is the fastest built-in option: open the PNG, go to File > Export As, change the format to JPEG, and save.
  • You can adjust the quality slider in the export dialog to control file size—higher quality means larger files.
  • Automator lets you convert entire folders of PNGs to JPG without opening each file separately.
  • Online converters work but require uploading your files to a website, so use them only for images you don't mind sharing.

Using Preview to convert one PNG at a time

Open Finder and locate your PNG file. Right-click it and select Open With, then choose Preview. Once the image opens, click the File menu at the top of the screen and select Export As. A dialog box appears with a dropdown menu that currently shows "PNG Image"—click that dropdown and select JPEG.

A quality slider appears below the format dropdown. Drag it to the right for higher quality (larger file size) or left for smaller file size. Most photos look good at the middle setting. Type a new filename if you want, or keep the same name—macOS will add the .jpg extension automatically. Choose where to save the file and click Save.

Your original PNG stays untouched. You now have both the PNG and a new JPG version in the same folder.

Converting multiple PNGs with Automator

If you have ten or more PNGs to convert, Automator saves time. Open Automator (search for it in Spotlight by pressing Command+Space, typing "Automator", and pressing Enter). Click File > New, then select Folder Action and click Create.

A dialog asks which folder to watch. Create a new folder called "PNG to Convert" or select an existing one where your PNGs live. Click Choose. On the left side of Automator, search for "Image" in the search box. Drag Change Type of Images into the workflow on the right. Set the dropdown to JPEG and the quality to your preference. Save the workflow with a clear name like "Convert PNG to JPG".

Now, any PNG you move into that folder converts to JPG automatically. The original PNG stays in the folder—the JPG appears alongside it. This method works in the background without opening Preview each time.

Adjusting quality and file size during conversion

JPG is a compressed format, meaning it trades some image detail for a smaller file size. PNG is uncompressed, so JPGs are always smaller. The quality slider in Preview controls how much detail you lose. At 100% quality, the JPG is still smaller than the PNG but looks nearly identical. At 50%, the file shrinks more but you may see slight blurriness or color banding, especially in photos with gradients or large solid color areas.

For photos and screenshots you plan to email or upload, 75% quality is usually the sweet spot—small enough to send quickly but detailed enough that most people won't notice the difference. For images you plan to print or edit further, use 90% or higher. Test by converting one image at different quality levels and comparing the results.

Using online converters if you prefer not to install software

Websites like CloudConvert, Zamzar, and Online-Convert let you upload a PNG and read a JPG without installing anything. Visit the site, click the upload button, select your PNG file, choose JPEG as the output format, and click Convert. The JPG downloads to your Downloads folder.

The downside is that your image travels across the internet to a stranger's server. For personal photos or sensitive images, this is a privacy risk. For screenshots, diagrams, or images you don't mind sharing, it's fine. These services are free but may show ads or limit how many files you convert per day.

Why you might want JPG instead of PNG

PNG files are larger because they store every pixel's exact color without compression. JPG compresses the image, making it smaller—usually 50 to 80% smaller than the PNG version. This matters when you're emailing files, uploading to websites, or storing hundreds of images. Most websites and social media platforms accept both, but JPG is faster to load.

PNG is better for images with text, logos, or areas of solid color, because compression can make those look blurry. JPG is better for photographs and complex images with many colors. If you're unsure which to use, convert to JPG and compare side by side—if the JPG looks good to you, the smaller file size is worth it.

Frequently Asked Questions

Can I convert JPG back to PNG on Mac?

Yes, the same methods work in reverse. Open the JPG in Preview, go to File > Export As, change the format to PNG, and save. PNG will be larger than the JPG because it's uncompressed, but the image quality won't improve—you can't recover detail that JPG compression removed.

Will converting PNG to JPG make the image blurry?

Not noticeably, if you keep the quality slider above 75%. JPG compression is designed to remove detail your eye can't see. Only very low quality settings (below 50%) produce visible blurriness. Test one image to see if the quality meets your needs.

What if I want to convert a PNG with a transparent background to JPG?

JPG doesn't support transparency, so the transparent areas become solid color—usually white or the background color you set. If you need to keep transparency, stick with PNG. If you don't need it, Preview will convert normally and fill transparent areas with white.

Can I batch convert PNGs to JPG without Automator?

Yes, using an online converter or a third-party app like ImageMagick (command-line tool for advanced users). For most people, Automator is the easiest built-in option. If you convert images regularly, a dedicated app like Batch Image Resizer may be worth the small purchase price.

Does converting PNG to JPG reduce quality?

Slightly, because JPG compression removes some color information. For photographs, the loss is invisible at quality settings above 80%. For images with text or sharp edges, the loss is more noticeable. Preview's quality slider lets you control the tradeoff between file size and visible quality.