Lady Agnew of Lochnaw by John Singer Sargent from the National Gallery of Scotland in Edinburgh. In the Wikipedia artice below it mentions that the painting is still in it’s original frame and may be the same one Sargent referenced as being almost too expensive at £20. A bemusing thought now given how the currency values have changed.

https://art.nationalgalleries.org/art-and-artists/5396/lady-agnew-lochnaw

https://en.wikipedia.org/wiki/Lady_Agnew_of_Lochnaw

https://en.wikipedia.org/wiki/John_Singer_Sargent