This is the 12149th most frequent Polish word.
malowane
"Malowane" means "painted" in English.
The word 'malowane' here acts as a past participle functioning descriptively to indicate that the walls have undergone the action of painting.
Ściany w pokoju są świeżo malowane.
The walls in the room are freshly painted.
The word 'malowane' in this sentence describes the paintings explicitly, indicating they are created with paint applied by hand.
Obrazy na wystawie są ręcznie malowane.
The paintings in the exhibition are hand-painted.
In this case, 'malowanej' (declined 'malowane') describes 'porcelanie' as having been ornamentally painted.