I know that 6x4 inch photos were popularized by 35mm cameras, which were then superseded by 4x3 aspect ratio in digital cameras, while 16x9 has taken precedence in general because of widescreen displays.
With this history in mind, what are the current prevailing conventions for fine art photography sizes in both pixels and inches, that would be both compatible in a gallery setting, large market printers, as well as for finding consumer frames for?
Equally important is the standard megabyte storage space these conventional sizes are approximated to consume?