However, that sensation of greenness seems to me totally subjective and is a property of our humanity. There's no objective greenness out there. For all I know, reality could be a totally colorless world.
How about for purposes of this discussion we agree that we all pretty much agree that the world is 'real', not a fiction in the dream of some amorphous caterpillar in some unknown universe? And let's hold our discussion to what is normally seen by physiologically intact adult humans.
What we talking about at the moment is the ease of defining certain terms. Colors are easily defined by their measured wavelengths. And we can describe the properties of a 'new' color to someone on the other side of the globe and she/he can accurately create that same color by working back from the definition.
Other words just aren't as easy to define. There are no 'controlling entities' as to what we mean when we use those words. If we were to agree to pick a standard, say the Oxford English Dictionary, and abide by it our communication would become easier. But we don't do that.
We use these words in idiosyncratic ways. Meanings morph from person to person, group to group, time to time. Take for example the words "cool" and "bomb". Cool can be hot, bomb can mean excellent.
As long as we continue to use poorly defined words we will continue to argue over the words and be distracted from discussing the photographs.
The solution? Don't have one.
A partial solution would perhaps be if people would make more of an attempt to describe in physical terms what it is about the image that strikes them.