The time dependence of the LOS-integrated mass ℳ (top panel) and emission intensity ℐ (bottom panel) in a sausage-oscillating cylinder for different “widths” of the LOS (pixel sizes). In all cases, the LOS is directed across the cylinder and passes through its centre. The red (solid) lines correspond to an infinitely thin line-of-sight, the blue (dotted) lines correspond to the pixel with the size of the half width of the cylinder w, the green (dashed) lines to 2w and the orange (dashed-dotted) lines to 3w lines, respectively. The black solid line in the bottom panel shows the relative variation in the density at the centre of the cylinder. The time is measured in the units t₀ = w/C_Ae.