Although the postcard this photo appears on is postmarked
#OnThisDay 21 June 1955, 70 years ago today, the image itself dates back to at least 1890.
A reverse image search led me to the special collections database of University of St Andrews where this photograph of Swallow Falls, Betws-y-Coed, was a part of Scottish photographer James Valentine's collection.
Flipping the postcard over and, sure enough, it's a "Silveresque" postcard published by Valentine & Sons Ltd of Dundee and London.
Other search results also show this photo has been reproduced many, many times.
The contents of the postcard message itself is addressed to Mary from what looks like Doris & Rosemary (I don't think I'm aware of who they were). They're visiting Betwys-y-Coed, enjoying the beautiful scenery, but found Colwyn Bay "too quiet for us".
https://collections.st-andrews.ac.uk/item/swallow-falls-betws-y-coed/36881
#JackAndMaryArchive #postcard #JamesValentine #victorian #BetwsYCoed #Conwy