Can't access the photo library on Safari (Monterey 12.6)

This is my first macOS-powered device, so excuse me if this is a lame question.

Whenever I am trying to upload a photo to Facebook (or any other website including this one,) in the dialog window I can only access photos from Media / Photos / Favorites, the rest of the images are simply not visible.

I tried to add Safari via Security & Privacy / Photos, but there are just no apps in the window that I could check.

What could be a workaround here?