This changes everything...

[MichaelPoole]

Depicting planets in true-to-life colours and intensities is extremely problematic. Neptune, for example, is bathed in sunlight which is 200 times less intensive than the light that illuminates Earth. So what would a human eye see in those conditions? Neptune would almost certainly look dark blue, but not very different to the colour of Uranus seen under the same conditions.

I basically completely agree with your post, but keep in mind 200x less intensive than daytime sunlight is still brighter than typical indoor lighting in people's houses on modern Earth. As for how that would look subjectively, see the reply to your second post quoted below.

A suitably augmented sophont could also adjust the perceived lighting intensity and saturation at will, which would allow them to detect subtle variations in colour and shade that would be invisible to human eyes. By recording the levels of light at particular wavelengths they could analyse and reproduce the results with considerable accuracy.

You're right though even baseline human eyesight very much adjusts based on light intensity, though not at will. I wouldn't be surprised that that pic would correspond to what an average Western person would see if they were teleported to a space capsule orbiting Neptune with a transparent window, but what they'd see after an hour of dark adaptation or if they're an experienced stargazer from a remote rural area may be very different.