How to Convert PNG to JPG on Windows: 4 Free Methods
For one file, open the PNG in Microsoft Photos and use Save As → JPEG. For batches of dozens, IrfanView is the fastest free Windows option.
Step-by-step
Open the PNG in Microsoft Photos and Save As JPEG
Windows 10 and 11 come with Microsoft Photos as the default image viewer. Open the PNG by double-clicking, click the three-dot menu, then Save As → JPEG. A quality slider appears with values from 0-100 — start at 85 for photos. Microsoft Photos preserves the original PNG and writes the new JPG to your chosen folder. This path requires no installation and handles any PNG size. The catch: Photos does not support batch conversion, so this is a one-at-a-time workflow only.
Use Paint for the simplest offline conversion
MS Paint (still bundled with Windows) opens PNG and saves as JPG via File → Save As → JPEG. It has no quality slider — Paint's JPEG output is fixed at roughly quality 90, which is fine for screenshots but creates unnecessarily large files for photos. Use Paint only for one-off conversions where you do not care about file size. For anything beyond a handful of files, skip to IrfanView or XnConvert for proper quality control and batch support.
Batch convert folders with IrfanView
IrfanView is the most-cited free batch image tool for Windows. Install it, open File → Batch Conversion (or press B), set the input folder, output format to JPG, and pick a quality value (85 is standard). The dialog shows a live preview of file sizes, lets you rename outputs with a pattern, and processes hundreds of files per minute. IrfanView runs entirely offline — files never leave your machine — which makes it ideal for confidential photos or large local libraries.
Use Paint.NET for quality control on a single file
Paint.NET is a free Windows image editor that sits between Paint and Photoshop. Open the PNG, then File → Save As → JPEG. The save dialog shows a quality slider and a live preview of file size at each setting — much more useful than Paint's fixed quality. Paint.NET supports plugins for advanced formats but for plain PNG-to-JPG the built-in save dialog is enough. It also handles transparency, letting you choose the background color before JPG export.
Run a PowerShell script for fully scripted batches
Windows 10/11 comes with PowerShell, which can call the built-in .NET System.Drawing library to convert PNG to JPG. A simple one-liner like `Get-ChildItem *.png | ForEach-Object { [System.Drawing.Image]::FromFile($_.FullName).Save($_.BaseName + '.jpg', [System.Drawing.Imaging.ImageFormat]::Jpeg) }` does folder-level conversion with no extra tools. For more control over quality, install XnConvert (the GUI version of nconvert CLI) and run it from PowerShell with custom arguments.
Verify and clean up
After conversion, spot-check 3-5 output JPGs in Microsoft Photos to confirm they look right. Windows-native conversion typically shrinks PNG photos by 60-80% at quality 85. If you used IrfanView's batch mode with a separate output folder, your source PNGs are untouched. Delete the originals only after verifying the JPGs opened correctly and the file sizes match expectations. Keep at least one source PNG if transparency matters — JPG cannot restore transparency once flattened.
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