This is the thing - if you're going to be like Apple and dictate design, you have to get it right. macOS and Apple hardware is not to everyone's taste, and they make mistakes, but they prototype and dogfood and iterate like crazy and they have thumbnails in the damn file picker.
When you're picking a file, you can even tap space to get a blown-up preview of an image or PRF. I use this feature almost every time I need to pick an image.
One thing I'll give Apple credit for is in the early days of OS X, they had (and perhaps still have, if it's the same thing) a document called Human Interface Guidelines. They actually did real experiments with real people and came up with a set of UI patterns that were proven by science to make software features and UI discoverable, usable, and clear, with the least amount of cognitive load.
Things like, the buttons on a dialog should should be a verb indicating the _action_ the user wants to take. Like "Run This" and "Go Back" instead of "Yes" and "No". (Or worse, the old Windows "OK" and "Cancel", which is rife with ambiguity in so many cases.)
And the tone of the document was that it was intended to be useful to _all_ user interface designers of all software and on all platforms, not just OS X. I just skimmed over the current edition and as far as I can tell, these days it's basically just about how to stay "on brand" with the Apple experience when writing your own UI.
> When you're picking a file, you can even tap space to get a blown-up preview of an image or PRF. I use this feature almost every time I need to pick an image.
Wait, what? That would have been super useful, but how was I supposed to find out?
It's not indicated anywhere visually. I don't even remember how I found out about it.
This is a downside of macOS and iOS design - lot of hidden gestures. For example, you can right-click the text title of a Finder window to open a quick navigation to all the parent folders of the current directory.
This works in every Finder window; if there's a window with files you can use Quick Look. I'm not sure if it's documented anywhere anymore, but it's been around 15 years.
When you're picking a file, you can even tap space to get a blown-up preview of an image or PRF. I use this feature almost every time I need to pick an image.