This couple married in 1907, and in light of the buttonhole worn by the woman, I wondered if it was a wedding photo.
Whilst I know the dress isn't necessarily black - it could be any dark colour in this b&w photo - I had thought that it was customary for brides to wear white/light colours following Queen Victoria's fashion setting?
Or perhaps this is a posed photo of the couple as guests at a wedding, not their own?
A date would help to pin it down.
Not a particularly affluent family, but in a secure job - by 1911 the man was a Signal Fitter for the GWR.