Linux typically doesn't rely on file extensions; it gets a files type using "magic numbers" within the file itself. Linux apps, including GNOME Files, may still use extensions to determine file type.

The way the Linux file system is laid out makes perfect sense. I've been using Linux for so many years that I can't imagine another file system making more sense. When I consider how the Windows file ...

There's a lot to learn about image files on the command line, from verifying file format to finding out where and when photos were taken and maybe even getting an unusual view of what they look like.