Re: I detest that
"Double click an image file with html as an extension and see what happens next. Does your OS launch GIMP or Chrome?"
I almost never double-click on anything, but just to please you ... Neither, actually. It opens in my favorite lite-weight image viewer. I only open images in GIMP when I'm in need of an image editor. But thanks for playing. (No Chrome here, I don't intentionally run any of the gookids b0rkenware, but that's not really germane to this conversation).
Suggestion: man magic
Suggestion 2: man file
Then ask yourself "Why does Windows execute fonts instead of reading them and displaying them like any sane operating system?"