This Coast dress, the label went missing when sent to dry cleaners, long maxi floral chiffon halter neck dress in size M has a lightly padded bust and jewels under the bust.
The colour is more like the second pic.
I think the dress is Size 12. Please read the measurements

Pit to pit 17 inches
Under bust 16 inches
Length from armpit 50 inches

Made from polyester chiffon fabric, the dress has a zip at the back.