You may find it difficult to read the verso text, so here it is for you.
The handwriting reads: F.E. Field aged 15; Amynora Field aged 11. Confirmed by the Bishop of Chichester 2 May 1877 at St Mary Magdalenes, St Leonards on Sea, Sussex.
The printed text reads: Cabinet by Henry Knight. Patronized by Her Majesty the Queen, Photographer to the Crown Prince & Crown Princess of Germany
The girls in this photograph are not bridesmaids, as I thought on first seeing this photograph. The photo celebrates confirmation. Confirmation was an important and serious event for many teenagers in Victorian Britain, as their surviving diaries can testify. Young people were confirmed in great swathes. Age at confirmation was often determined by the timing of a bishop's visit.