A pale strapped dress with a side opening creates a longer narrow shape in this reference. Fine straps lead into a V neckline. Folds run towards the waist on one side, with part of a leg visible below. Pale strappy shoes and a small necklace complete the look. The mirror at the edge does not reveal the full back. Shine and draping are visible features, without proving silk, a particular construction or stretch.
For the outfit comparison, consider the relationship between side folds and opening. Hold your bag beside that area and then at the opposite side during a fitting. Decide which arrangement you enjoy and can use. Sit without carefully resetting the folds first and check your preferred coverage. Add a clear rear view of the actual model. Fine straps and a necklace in the picture do not resolve your underwear question. If you only want the draping idea, investigate it in another colour that suits the invitation and your chosen focus.