roomephantDo I still need a tape measure?
Yes, for anything where centimetres decide the outcome. A photo preview and a tape measure answer different questions, and mixing them up is how people end up with furniture stuck in a hallway.
What a preview settles well: whether a piece looks right against your wall, whether it dominates the room, how it sits next to what you already own, and which of two sizes to pick. These are proportion questions, and proportion is exactly what a picture carries.
What only a tape measure settles: doorway clearance, whether a drawer opens with the bed in place, whether the radiator stays uncovered, and any gap under about 10 cm. These are the cases where being slightly wrong costs you a delivery.
The honest reason for the split: scale in a photograph is estimated, not surveyed. We read it from what is in the picture — doors, windows, skirting, furniture already there. That estimate is good enough to judge proportion and not good enough to certify a 3 cm gap.
So the useful order is: preview first, to narrow to one or two options quickly, then measure the one you are about to buy.