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Sep 7, 2026
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XL Converter is a free, open-source batch image converter for Windows and Linux from Code Poems that turns photos into JPEG XL, AVIF, WebP or smaller JPEGs, shrinks existing JPEGs without loss and downscales whole folders in parallel.
XL Converter is a free, open-source batch image converter for Windows and Linux built around the two formats that shrink photos the most, JPEG XL and AVIF, with WebP, JPEG and PNG alongside them.
Drop a folder of images on it, pick an output format and a quality, and it encodes everything in parallel using all of your CPU cores.
It is GPL-licensed, works offline, and carries no ads, no telemetry and no paid tier.
What XL Converter Actually Does
The main job is batch conversion into a modern format. JPEG XL and AVIF hold the same visible quality as a JPEG at a fraction of the size, and XL Converter uses the current reference encoders for both - libjxl 0.12 and AOM AV1 3.14 as of version 1.3.0, with SVT-AV1-PSY available as an alternative AVIF encoder.
If you need to stay on plain JPEG, the JPEGLI encoder produces files that any browser or viewer opens but that are up to 35 percent smaller than a conventional JPEG at the same quality.
Beyond format changes, it downscales by width, height, percentage, megapixels or shortest or longest side, keeps your folder structure intact on output, and preserves metadata through ExifTool with editable presets.
Lossless JPEG transcoding: XL Converter can wrap an existing JPEG inside a JPEG XL container, cutting the file by 16 to 22 percent without changing a single pixel - and the original JPEG can be reconstructed bit for bit later.
The Windows Defender Warning
The installer is regularly flagged by Windows Defender's machine-learning detection, with a name ending in !ml. The developer has documented this on every recent release: the program is a Python application packaged with PyInstaller, and that packaging method trips heuristic scanners on a regular basis.
The releases are scanned with several other antivirus engines and come up clean, and the source is public. If Defender blocks it, add the program to exclusions or submit it to Microsoft as a false positive. The portable build in a .7z archive is the same code and gets the same warning.
Check the source: a false-positive warning is only safe to dismiss when the file came from the developer's GitHub releases or a mirror of them. A copy from anywhere else deserves the suspicion.
Which File to Download
The download page carries three files for version 1.3.0, all 64-bit only:
| File | Platform | Use it when |
|---|---|---|
| xl-converter-win-1.3.0-x86_64.exe | Windows | You want Start menu shortcuts and easy updates - the normal choice. |
| xl-converter-win-1.3.0-x86_64-portable.7z | Windows | You want to run it from a USB stick or keep settings with the program. Needs 7-Zip or similar to extract. |
| xl-converter-linux-1.3.0-x86_64.AppImage | Linux | Any distribution - mark it executable and run it, nothing to install. |
There is no supported Mac version. A macOS beta exists but the developer has deprecated it and recommends running the Windows build under Wine instead. There is no 32-bit or ARM Windows build either.
Viewing What You Made
Converting to JPEG XL or AVIF is the easy half; Windows does not open either format out of the box, so a freshly converted folder can look broken in File Explorer.
For JPEG XL, our guide on how to view JPEG XL files on Windows walks through the options.
The short version: Microsoft's own JPEG XL Image Extension on Windows 11 24H2 or newer, or the free JXL Winthumb decoder on anything older.
For AVIF, the AV1 Video Extension from Microsoft is what gives Explorer and Photos AVIF support. For WebP, the WebP Codec does the same job.
On the input side, iPhone photos arrive as HEIC, and XL Converter reads them - but Windows needs the HEIF Image Extensions or the free WIC for HEIC before Explorer will show you which ones you are converting.
What Changed in XL Converter 1.3.0
Version 1.3.0 shipped on 6 September 2026 and is the current stable release.
- New: a PNG Optimization mode using Oxipng, a process priority setting, and more resampling algorithms for downscaling.
- Faster: conversions start and cancel more quickly, and JPEG and PNG sources below the downscaling threshold are processed faster.
- Encoders: libjxl updated to 0.12.0 and AOM AV1 to 3.14.1, with Oxipng, ExifTool and ImageMagick refreshed too.
- AVIF: the tune setting now applies to colour only and leaves the alpha channel at default.
- Fixed: a performance problem on 128-thread CPUs, temp files left behind after cancelling a downscale, Delete Original failing on virtual drives on Windows, and case-sensitive extension filters in the Add Files dialog on Linux.
Who Should Look Elsewhere
The tell is your output format. If the files you need to produce are JPEG, PNG or TIFF for someone else's software, XL Converter's advantages barely apply and a general-purpose batch tool has more knobs.
XnConvert reads and writes more than 500 formats and adds watermarks, effects and renaming. Converseen is the lighter open-source equivalent and also runs on macOS.
If resizing is the whole job, Light Image Resizer and FastStone Photo Resizer are faster to learn.
For editing individual pictures rather than converting folders, paint.net and GIMP both save to JPEG XL and AVIF now.
Camera RAW files are the other boundary. XL Converter is not a RAW developer - process them in darktable or RawTherapee first, then hand the exported files to XL Converter for the final compression.
More converters and viewers are in the Graphics category, and the HALIC lossless image guide covers a newer format XL Converter does not write yet.
Quick questions
Is XL Converter free?
Yes, completely. It is open source under the GPLv3, with no paid version, no trial limits, no ads and no telemetry.
Why does Windows Defender say XL Converter is a virus?
It is a false positive from Defender's machine-learning scanner, caused by the PyInstaller packaging rather than anything in the program. The developer documents it on every release, other scanners report the files clean, and the source code is public. Add it to exclusions if you downloaded it from GitHub or from here.
JPEG XL or AVIF - which should I pick?
JPEG XL if you are archiving photos: it is faster to encode, handles large images and lossless well, and can wrap existing JPEGs without loss. AVIF if the images are going on the web, because every current browser displays it, while JPEG XL still depends on the browser.
Does XL Converter run on macOS?
Not officially. There was a macOS beta, but the developer has deprecated it and suggests running the Windows version through Wine. Converseen or XnConvert are the native Mac alternatives.
Does it keep my photo metadata?
Yes, through ExifTool. The metadata presets are editable, so you can keep everything, strip GPS only, or remove it all.
Is the portable version limited?
No. It is the same program in a .7z archive without an installer, and it keeps its settings in its own folder so you can move it between machines.
Download XL Converter 1.3.0 and see how much smaller your photos get, or tell us how you got on if you have used it before.
