A shopper returning a dress because it did not suit them and a shopper returning it because it was two sizes off are two different problems, and only one of them is solved by seeing a picture.
Most virtual try-on apps generate an image from a shopper photo. That answers "what does this look like on me?" and it genuinely helps with the styling half of returns. But it does not collect measurements, so it cannot answer "which size do I order?" - and per Coresight, that is the half causing most of the damage.
This is the practical filter when you are evaluating apps. Ask whether the tool collects body measurements, and whether it outputs a size rather than only a picture. Our roundup of Shopify try-on apps lists which ones document a size recommendation - of the six we verified, one does.
The related trap is bracketing: shoppers who deliberately order two or three sizes intending to return the rest. Bracketing is a sizing-confidence failure that shows up as a conversion win and a returns disaster. If you are measuring try-on impact, watch units per order alongside return rate, or a drop in bracketing will look like a drop in sales.