The whole job is seeing your silhouette
Photo-based measurement works by inferring a 3D shape from a 2D image. Every layer of loose fabric adds a discrepancy between what the camera sees and what your body actually is.
Best options
- A fitted t-shirt or tank top.
- Leggings or slim trousers.
- Sportswear that is snug but not skin-tight.
- Nothing with padding, structure or stiff fabric.
Avoid
- Anything loose, flowing or oversized.
- Skirts or dresses that hide the hip line.
- Bulky knitwear, especially jumpers.
- Items with belts, sashes or ties that obscure the waist.
- Large jewellery, especially long necklaces.
Why the waist is the critical zone
It is the measurement the system finds hardest. Published smartphone validation reports errors of around 6.1 cm at the waist, against 2.5 cm at the arm.
The waist is also where loose clothing does the most damage. A tucked-in or clearly delineated waist gives the system something to work with.
If your top is baggy at the waist, no amount of photographic accuracy elsewhere will save that measurement.
Footwear and stance
Wear the shoes you would normally wear, since inseam depends on where trousers sit on the shoe. Stand naturally with weight distributed evenly, rather than shifting onto one hip.
Lighting matters more than people expect
Even, diffuse light is what you want. Hard directional light creates shadows the system may interpret as body shape. Avoid direct sunlight and strong backlighting.
The simplest test is whether you can see your shadow. If you can, the light is too directional.
Hair and other details
Long hair covering the shoulders interferes with shoulder width estimation. Move it forward, or tie it back before capturing.
Stand against a plain background with space around you so limbs are distinguishable from your torso.
Before and after
Check that your silhouette is clearly visible and that your waist is delineated before capturing. Ten seconds of adjustment is usually the difference between a good scan and a poor one.
More detail in how photo measurement works.