A black full-skirt midi shows a plain broad skirt, defined waistline and wide curved lower edge above dark pointed pumps in a complete view.
The lower half is largely free of visible pattern, making the outline easy to identify. Its edge creates a broader curve above the shoes than the narrow black comparison. If you want a similar shape, look at both feet in an ordinary stance. A spread-skirt pose can show extra width, but should not become the only view used for the decision.
Dark pumps provide a closed pointed shape beneath it. Try your own pair with the dress unchanged first. Decide whether you prefer that finish or a more open line. A different shoe can alter the lower picture without requiring the midi length itself to change.
Include a normal step in the fitting. Observe where the broad edge sits and how much shoe remains visible. The high sleeveless upper line is an additional style choice rather than the explanation for the lower shape. Material and possible alterations are not documented by the photograph and need a separate examination of the actual garment.