I would like to know: is it possible to see a grid of Thumbnails,
in the File-Open dialog box, of programs, such a Firefox, (xxx)Writer, Image editors that don't generate their own thumbnails library.
Note: I'm NOT talking about a file-manager, not talking about just one program, but the OS at large.

Is there a Desktop Environment that can provide this functionality?
Or are the Apps in Linux just not looking for an API that would give them that?
Isn't the common file-open-dialog not modifiable, so that it can replicate such a feature to the entire OS?

Some programs like gThumb will show thumbnails - but in my testing on Xfce and gnome-derivatives, this feature's absence seems to be generally absent, with only a list available (sometimes with one preview at a time, but no tn grid).

Why? (normally one wouldn't have to justify this, but the fact that I've not yet found a distro that supports this feature, tells me that some may need an explanation)
Most people have directories with family photos, photos of special interest, memes for social media, etc. And since approximately "forever" in Windoze and Appel (and Android too), when we go to open a file, no matter what the app, we get the choice of viewing as a List, icons, or Thumbnails - and we can even adjust the size. This is invaluable when searching for that one photo, among hundreds, that are all named a sequential number by a digital camera (or some long random number if from FB, or other image repository).

How could it be that this feature seems to have gone under the radar for so long?

Here is an example, of File-Open in Windoze, to add an image to a post/comment on FB through the FireFox browser:

Attached Thumbnails