Size is decided on the wall
The common mistake is choosing the work first and discovering later that it reads as a postage stamp on the wall. Format is not a property of the work: it is a relationship between the work, the wall, and the distance you look from.
The two-thirds rule
Above a piece of furniture — sofa, console, sideboard, headboard — the work or group should occupy roughly two thirds of the furniture's width. Narrower and it looks lost; wider and it crushes the furniture.
Height is measured from the eye
The centre of the work sits about 145-150 cm from the floor: average standing eye level, and the reason museums hang everything at the same height. Above a sofa, though, the distance from the back wins: leave 20-30 cm between the top of the furniture and the bottom edge of the work, or the two read as a single object.
Viewing distance changes everything
A corridor is seen from a metre away: a 40 × 30 cm format is perfect there, and a large one cannot even be taken in. A living room is seen from three or four metres, and there a small format belongs in a group, not alone.



