An all-black suit is photographed on a chair, with a dark shirt and dark neckwear continuing the jacket’s colour arrangement. The bent legs and supported arm make the seated shape visible in a way the standing references do not. Reflections separate some surfaces, but the picture does not establish their fibre, whether they match exactly in person or how the garment feels in that position.
Use the image as a reason to include a real seated comparison. Try the intended inner layer, sit normally and notice pressure at the waistband, knees and jacket front separately. Stand again without first arranging every area by hand. If something needs adjustment, describe the exact location and movement to the fitter rather than assuming a dark continuous look should fit closely everywhere.
Compare the colours in ordinary light before deciding that you want an uninterrupted effect. You may enjoy a small difference between jacket and shirt. Add shoes and an outer layer to judge the full outfit, and check the invitation independently. A seated photograph cannot supply a complete standing proportion or establish comfort for a long meal.