The image grid feature is now live in the 2022.12-rc branch.
<3 Thank you very much for all the feedback and support! <3
One known issue is that the grid is not generated in "quote shared" post, and I did not find the time to analyze / address it (github.com/friendica/friendica…).
@marek@grischa Don't worry about it, it's an issue with the fancybox addon specifically, and you need an image grid with two columns, it doesn't affect inline images like you've shared.
@hypolite@grischa I am not able to confirm the issue. On my dev instance, clicking on any image in any of both column starts fancybox correctly (Tested it here: friendica-dev.mbbit.de/display…). Can you provide an example? Thank You!