بِسْمِ اللهِ الرَّحْمنِ الرَّحِيمِ
"The angels do not enter a house in which there is a dog or a portrait"
[Al-Bukhari and Muslim]
Angels here refers to angels of mercy whose visit is a blessing for homes;the angels who supervise us and record our deeds are with us at all times.
From Riyad Us Saliheen Vol Two
Page # 1254 Hadith # 1684.