Why you can't see it day to day
Light, posture, what you ate and how far you stood from the phone all change a photo more than a week does. Compare two photos taken differently and you're mostly comparing the setup.
Pick one angle
Front or side, the same one every time. The side shows posture and outline that a front photo flattens. If you want more than one angle, give each its own journey, so every photo lines up with others taken the same way.
Same setup every time
One spot, one light, the phone at the same height and distance, and the same pose. An outline of you from an earlier photo, traced over the camera, lets you line up before you shoot, so your feet and your shoulders land where they did last time.
Wear the same thing
Pick one fitted outfit and keep it for every photo. How it sits on you becomes a reference point in itself, and loose clothes hide the outline you're trying to see.
Compare the right way
Compare photos at least two weeks apart, better four, never neighboring days:
- Slider: drag across the waist and shoulders and watch the outline move.
- Side by side: step back from the screen and look at the whole shape.
- Timeline: play every photo in order to see the direction, not one jump.
Already started? Use an old photo
If you began before you took photos, import an older photo of yourself as the before. It won't match your new setup exactly, but it marks where you started, and every photo after it can be taken the same way.