https://forum.inaturalist.org/t/get-ready-for-a-whole-bunch-of-changes-to-taxon-photos/61913
https://forum.inaturalist.org/t/lock-taxon-photos-for-the-most-observed-taxa/50288
You can. But weigh up your change first - we have history - so everyone can see - who changed the picture, when.
https://help.inaturalist.org/en/support/solutions/articles/151000184018-what-guidelines-should-i-follow-when-choosing-taxon-photos-