Dragonflies are one of my favourite insects but that pixie looks far too large for it, or perhaps being a creature of magic it is as light as gossamer. The Fairy Lake, painted by LR Steele who did a lot of paintings of fairy tales and mythology for the postcard publishers Salmon. The lake portrayed as magical place, I love the colours. The pointed ears and caps I think suggest Pixies, a part of Celtic folklore who are rather mischievous so indeed would have fun riding fish. In country districts in times past a bowl of milk and bread would be put outside so that pixies wouldn't play pranks on the owner. Of course fairies were more benign creatures but they also liked to test humans. No wings are evident on the lilly pad fairy, maybe she has tucked them away, or perhaps is an enchanted child.
The card was sent on 17 September 1947 from an aunt staying in Ross on Wye, (a pretty place lying on a bend of the River Wye on the Welsh borders, and if anywhere were to have a fairy lake it would be there), to her niece. A nice clear postmark but the message was written in pencil so has faded
but Auntie says "Just to let you know I am having a lovely holiday"