This card was sent by “Mary” to Annie Barber in May 1910:

Marie Studholme was a well known actress and singer. Given the topic of the sender’s message, perhaps the card was chosen because of the splendid hat she is wearing? The sender Mary, gives Annie Barber quite detailed instructions about how to trim a hat:

The message reads
“Dear Annie, When you trim my hat do not show all those long green stems of the poppies as they are a nasty colour green and do not go with my blue costume. I like the stems of the pink flowers, you can show them as they are a nice colour. Forgot to tell you on Saturday. Mary”
Before her marriage to George Barber Annie worked as a milliner, as shown in the 1891 census when she was living with her parents in Hornsey Park Road, Wood Green, so it’s no surprise to find her trimming hats in 1910, although she has presumably given up working. The census also shows that Mary is Annie’s younger sister.