The image shows a speed limit sign (40 km/h) placed next to a population sign (“MUROS”). This means that the speed limit applies throughout the entire town unless another sign within the town modifies or cancels it.
In Spain, when a speed limit sign appears at the entrance of a town, it applies to all roads inside the town unless changed by another sign.
If another sign inside the town indicates a different speed limit, that new limit will override the initial one.
If no other signs appear, the 40 km/h limit remains valid throughout the town.