No. Taking photos and sharing them are not ruining travel, they’re actually improving them.
When I share a travel photo I have one specific goal: to promote the place, because tourism is an industry that benefits the local and can’t be outsourced.
My recent travel to Spain has already inspired a friend to alter his itinerary.
My friend’s photos from Turkey have moved it up in the queue of places I’d like to visit.
And my home country Indonesia can always use a tourism boost to catch up with neighbouring countries.
Update 27 July 2016:
Research has also shown it can boost enjoyment of the trip. Happy tourists will spend more, recommend more, and might even return for repeated enjoyment.