In that photo, the gallery art in question occupies less than 1/4 of the frame, and is partly obscured. The photo is composed primarily of green background, contrasted with a blonde girl in red.
I don't understand how that is a 'reproduction' photo at all.
I don't understand how you can have read the page I linked to and have come away with the impression that I was in any way referring to that specific photo.
See the "Digital image (c) Tate, London" watermark on the image? Given that the original painting is 122 years old and therefore well out of copyright itself, the gallery are asserting that there is copyright in the photograph of the painting.
Having a quick google around, there's an interesting short article at http://www.museumscopyright.org.uk/bridge.htm about a US case brought by a UK company which seems to clarify that the position is different in the US and in the UK: in the UK, there is still presumed to be copyright in photographs of artwork, while there is not in the US, so it's a little more complicated than I thought (who knew?).
I don't understand how that is a 'reproduction' photo at all.