I wondered - twice.

Wonder #1 - Sitting making short work of an All Day Breakfast in the Cafe in K/Stephen; where we concluded, after JK & Clicky had concluded their business. Wonder - WHO the heck was "Frank?"

We, sort of, by consensus, aimed for said Bridge, as it had been mentioned, at least once previously. 
I looked up Frank and added it to the scene we saw on the Cafe wall.  
It kind of explains why such a sturdy Bridge to nowhere was only a foot-bridge; the path beyond wasn't even a Gravel path.

Wonder #2 - Didn't really occur until home and mounted on the "Disputer".  Namely - WHAT D-eck are those two dark patches on the painting?

Being a(n) nosey old sod enquiring mind, I actually shot, both the open hole and the bricked up one - BUT - I had to get them up for editing B4 the light dawned; namely - that's what we can see on the painting.

(I doubt it'll show on the "enbiggered" shot, but I could make it vastly BIGGER during editing and can see one hole under the right hand arch.)
Shown in Rt hand extra.

ADDENDUM:- I missed the explanation of why it was there - silly old B@£$%^&*

"The bridge is a grade II scheduled monument, a corpse lane bridge, being a stone built double arched packhorse bridge dating to the 17th century. Its original purpose was to provide for the conveying of coffins between the nearby villages of Hartley and Winton to St Stephens Church (the cathedral of the Dales) which is very close to Frank's Bridge."

Software playing sillibeggars again?  Nearly lost it - had to publish then return to add both location AND Extra.
( :¬o)