Why is the transverse spatial extent of a photon proportional to its wavelength which is a longitudinal quantity?

In quantum mechanics, particularly the wave-particle theory, it states that light behaves like a wave or a particle. For the wave behavior, its movement is measured in wavelengths while the time for each wavelength is the frequency. For the particle behavior, according to Planck, the energy of the photon (light particle) is determined as

E = hc/wavelength, where h is the Planck's constant (6.626 x 10-34 J-s per particle) and c is the speed of light ( 3 x 10^8m/s)

As you can see, the energy of the photon is INVERSELY PROPORTIONAL to the wavelength with the Planck's constant as the constant of proportionality.

A clear cloudless day-time sky is blue because molecules in the air scatter blue light from the sun more than they scatter red light.