How to Convert PNG to JPG on Mac (Free, No Upload)

13 June 2026

👉 Just need the tool? Convert PNG to JPG — runs in your browser, nothing uploaded.

You have a PNG that is too large to email, or a site that only accepts JPGs, and you need it converted now without installing anything. On a Mac you have two good ways to do this: the Preview app that ships with macOS, and a browser-based converter. Both are free, and which one fits depends on how many files you have and how much control you want.

First, a quick reason it matters. PNG uses lossless compression and supports transparency, which makes it great for screenshots, logos, and graphics with sharp edges. JPG uses lossy compression tuned for photographs, so it usually produces much smaller files for photo-like images. Converting PNG to JPG is most useful when you want a smaller file for sharing or upload.

Convert with Preview (already installed)

For one file or a few, Preview is the fastest path.

1. Open the PNG in Preview (double-click it, or right-click and choose Open With > Preview).
2. In the menu bar, choose File > Export.
3. Set the Format dropdown to JPEG.
4. Drag the Quality slider to balance file size against image quality. Higher quality means a larger file.
5. Pick a save location and click Save.

If you don’t see JPEG in the Format list, hold the Option key while clicking the dropdown to reveal the full set of formats. Preview leaves the original PNG untouched and writes a new JPG.

Batch convert several PNGs at once

Exporting files one at a time is tedious, and Preview can handle a batch. Select the PNGs in Finder, open them together in Preview (they appear in the left sidebar), select all of them in that sidebar with Cmd+A, then choose File > Export Selected Images. You pick one destination and one set of format and quality settings for the whole group.

For larger batches, or when you just want a single quality setting without managing the sidebar, an in-browser tool is often simpler. With Convert PNG to JPG you can drop in many files at once, set one quality level, and download the results together. The conversion runs entirely in your browser, so the images never leave your Mac, which matters if the files are personal or confidential.

The transparency caveat

This is the part of PNG-to-JPG conversion that surprises people, so it is worth understanding before you convert anything important.

JPG has no alpha channel, so it cannot store transparency. Every JPG pixel is fully opaque. When a PNG with transparent areas becomes a JPG, those transparent pixels have to be filled with a solid color.

The catch on a Mac: Preview fills the transparent areas with black, and it gives you no setting to change that. So a logo saved as a transparent PNG can come out of a Preview export sitting on a black rectangle, which is rarely what you want. Different tools choose different fill colors, so do not assume it will be white.

If you specifically need a white background, you can force it from Terminal with the sips command:

sips -s format jpeg --padColor FFFFFF -o output.jpg input.png

That replaces the formerly transparent pixels with white (FFFFFF). You can swap in any hex color.

If you need transparency preserved at all, the answer is simpler: do not convert to JPG. Keep the PNG, or convert to a format that supports an alpha channel, such as WebP (which supports transparency for both lossy and lossless images) or AVIF.

Choosing a quality setting

JPG is lossy, so every save discards some image data, and that loss is permanent. For most photos, a fairly high quality setting looks almost indistinguishable from the original while cutting the file size substantially. Pushing the slider low introduces visible artifacts, especially around text and sharp edges, which is also why JPG is a poor fit for screenshots of text.

One thing to keep in mind: repeatedly converting and re-saving the same JPG compounds the quality loss with each pass. If you might edit the image again, keep the original PNG as your master copy and export JPGs from it as needed.

Which method should you use?

For a one-off conversion, Preview is the obvious choice since it is built in and takes seconds, as long as the image has no transparency you care about. For a folder of images, or when you want a predictable single quality setting and a quick download of everything at once, the Convert PNG to JPG tool is usually less fiddly.

In short: reach for JPG when you are working with photos or images that already have a solid background and you want a smaller file. Keep your PNGs, or use WebP, whenever transparency or pixel-perfect text matters. When in doubt, convert a copy and compare the two before deleting the original.

Convert PNG to JPG →