I agree tangible visible guidelines would be really helpful ( if they don’t already exist )
I´ve noticed several times on taxa where I have altered the photos somebody else has reverted or swiftly changed them one day later. At present I don’t want to flag taxa for discussion around this tbh, it feels like a minefield / time-sink given how subjective it is.
And I’m not sure taxon history is that helpful either, as it just makes it more frustrating in some ways.
In the end I decided changing taxon photos in the current system feels like a waste of time, so I’ve largely given up…at least at higher levels or with more common taxa.
Longer term perhaps there could be some sort of voting system to make good photos harder to flip so that one’s input feels like it has more longevity / meaning.
There is discussion here around toggling some taxon photos to curator-only editting :
https://forum.inaturalist.org/t/normal-users-change-taxon-page-photos/4551/10
I think this could make sense for higher levels and common taxa.