XnView Software

XnView: MP 1.5.3 64 bit
Linux Mint 64 bit

JPEG-XL .jxl files created with JPEG XL image format reference implementation libjxl v0.9.0 cannot be opened with XnViewMP.

Effect: Error message: "my_error_exit...<Not a JPEG file: starts with 0x00 0x00>"

To reproduce:
1. Create image with latest cjxl: 2. Open out.jxl in XnViewMP

Actual behaviour (bug): File doesn't show. Error message in terminal.

Expected behaviour: Display JPEG-XL in all its glory.

XnViewMP use jpegxl library 0.70. So it is possible, that you could not open files, which were created by a newer version.
There are a few picture editing programs only, which support the latest stable version 0.82.
You can test it with Paint.net (Windows) or The Gimp (Windows/Linux), which could be able the load jpg xl format 0.8x.
IrfanView (Windows) support JPEG XL, too. But it could be an early version 0.60 or 0.70.

Your jpeg xl encoder/decoder release 0.90 should be nightly build or beta release.

I was not able to download v. 1.5.3 (download starts but fails after a few seconds), but I could made some tests with v. 1.5.2 (on win 10 64 pro). Jxl files generated from png (using lossly coversion) or jpg (using lossless conversion, i.e. direct transcoding) with cjxl 0.9.0 can be read without any issue by XnViemMP v.1.5.2). According to jxl developers, the jxl code is "frozen' so that old versions of the decoder should be able to run on jxl images generated by recent versions of the encoder, and vice-versa. Maybe a specific issue with v. 1.5.3 ?

Currently i have problems to build latest version of libjxl.

But i've tried to convert png&jpg files with cjxl (0.8.1) and no problem to view them...