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How-To Guide

How to Convert PNG to JPG on Mac

macOS has built-in tools that make PNG to JPG conversion effortless — no downloads required. Preview, Automator, and the command-line tool sips can all convert PNG images to JPG individually or in batch. This guide covers all three methods so you can pick the one that suits your workflow.

Open PNG to JPG Converter

Step-by-step instructions

  1. 1

    Convert using Preview (easiest)

    Open the PNG file in Preview. Go to File → Export. In the Format dropdown, choose JPEG. Drag the Quality slider to set compression (85–90% is a good default). Click Save. For multiple files: select all PNGs in Finder, right-click → Open With → Preview. In Preview, go to Edit → Select All, then File → Export Selected Images.

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  2. 2

    Batch convert with Automator

    Open Automator (Applications → Automator). Create a new workflow as Quick Action or Folder Action. Search for 'Change Type of Images' and add it. Set the action to change images to JPEG. Optionally add 'Scale Images' before if you want to resize. Run the workflow on your PNG files — Automator processes them in place with an option to keep originals.

  3. 3

    Command line with sips

    Open Terminal. For a single file: `sips -s format jpeg input.png --out output.jpg`. To set JPEG quality (0.0–1.0): `sips -s format jpeg -s formatOptions 0.85 input.png --out output.jpg`. Batch convert all PNGs in a folder: `for f in *.png; do sips -s format jpeg "$f" --out "${f%.png}.jpg"; done`. sips is pre-installed on every Mac — no installation needed.

  4. 4

    Check the output

    Open the converted JPG in Preview to verify quality and appearance. PNG backgrounds that were transparent will be filled with white (JPG has no transparency support). If you need transparency preserved, keep the PNG or convert to WebP instead. Compare file sizes — JPG should be significantly smaller than PNG for photographs.

Why convert PNG to JPG?

PNG files are ideal for screenshots, graphics, and transparency, but they're much larger than JPG for photographs. Converting PNG photos to JPG reduces file size by 60–80% while maintaining visually identical quality — essential for web performance, email attachments, and storage.

Your files never leave your device

FormatDrop runs the conversion engine entirely inside your browser using WebAssembly. No file upload. No server. Nothing stored. You can verify this by opening DevTools → Network tab and watching: zero upload requests.

Frequently asked questions

Does converting PNG to JPG lose quality on Mac?
Yes. JPG uses lossy compression, so converting PNG (lossless) to JPG always introduces some quality loss. At 85–90% JPEG quality the difference is usually invisible to the naked eye. Never convert a JPG back to PNG and then back to JPG — each round-trip degrades quality further.
What happens to PNG transparency when converting to JPG?
Transparent pixels are filled with white (sips) or the selected background colour (Preview). JPG has no alpha channel. If your PNG has important transparency (logos, cutouts), keep it as PNG or convert to WebP, which supports transparency with better compression.
Can I batch convert PNG to JPG on Mac without Automator?
Yes — use the sips loop in Terminal: `for f in *.png; do sips -s format jpeg "$f" --out "${f%.png}.jpg"; done`. This converts every PNG in the current directory. FFmpeg also batch-converts: `for f in *.png; do ffmpeg -i "$f" "${f%.png}.jpg"; done`.
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