LynxChan uses file mime-type filter to keep our anons safe. This the official thread to add new items or anything we missed.

What file types do we don't support that you would like us to add?

IF YOU ARE HAVING A PROBLEM WITH UPLOADING A FILE, TEST HERE AND LET USE KNOW THE MIME TYPE YOU GET:
http://mime.ritey.com

Here's the current list:
"image/apng",
"image/png",
"image/jpeg",
"image/jxl",
"image/jxr",
"image/jp2",
"image/jpm",
"image/jpx",
"image/mj2",