The red photograph combines a rear view with an additional front reflection. Fine upper and lower crossings run across the open back. A smaller triangular opening remains near the lower boundary, with tied ends hanging beneath it. In the mirror, a front V line and an opening in the long skirt are visible. Part of a pale open shoe appears there, while one hand holds a side section of the skirt.
The simultaneous information is particularly useful for comparison: a prominent back can accompany a front that is also open. Each decision deserves separate attention. The hand at the skirt also changes its distribution at that moment. Do not assume that the resulting width or opening describes the garment in an ordinary, untouched stance.
Ask to see the actual model from front and rear without sideways lifting. Then check your intended underlayers from both sides. The small shoe area in the mirror suggests a shape, but shows neither a complete pair nor the required hem length. Treat this detail as an addition to a fitting, rather than a substitute for the missing full views.