The format of an image is very interesting
We humans perceive different course formats, but there are things that make most people see a format more appealing than another. Squared format is often perceived positively. An almost square format is not perceived as positive. A rectangular formats can have an eye for the ideal relationship, the so called golden rectangle.
A-format (1:1,414) is crazy for images and should not in my view be at all for photo. There is only one standard for plain paper. American standard (1:1,294) är ännu värre.
In art and more serious photo you talk about the golden rectangle. It has the ratio 1:1,6 which is perceived much more pleasant to the eye. No coincidence that even many flags have this relationship. Surely no coincidence that the Mona Lisa's facial features is also based on the mathematics. Many other works of art also utilizes this relationship. the formula is 1 + (ret ur 5) divided by 2 = 1,618.