I made these three white "slip" dresses from Simplicity Pattern 5226 variation B.
Alteration to the pattern is that I fully lined the bodice of the dress instead of using the bias strip edging on the neck & sleeves.
These are size 3,5,7 for my daughters and niece for a family photo we're having done with all of us. I machine embroidered the first initial of each girl on the front and added decorative machine stitching near the hem where the topstitching would be to hold the gathered piece on. I think they turned out gorgeous and would look good in one of those "on the beach" family photos!