This subject has fascinated me for ages! Almost every culture has its own take on this issue. My late grandmother used to tell me that we shouldn't play outside after dark and that babies shouldn't be outside after sunset because that's when they are more attuned and susceptible to spirits. The term "witching hour", which refers to babies crying at certain times of the day for no reason, obviously originated from a belief that babies are vulnerable to supernatural beings. Of course now, we can attribute this to baby being tired by the end of the day and other logical reasons. Personally, I believe that babies in general are much more sensitive to their surroundings. Whether or not they can see supernatural beings, it's really up to interpretation and cultural beliefs. As for the painting, perhaps baby is simply amused by the colours or composition of it. If it really freaks you out, perhaps you can try removing it from the hallway for a while and see if there are any changes.
Just recently, we went on a trip with our friend who brought along her family. On the first night, our friend suddenly came down with fever and her parents felt that it could be due to supernatural “things” in the room because their 3-month old was crying and fussing non stop since they reached the place. They did some simple prayer and baby calmed down for the rest of the night. Sends chills down my spine just thinking about it (and we stayed just next door to them). I think it is open to interpretation but in general, babies (and erm dogs) are often believed to be more sensitive to such supernatural occurrences. For me, I choose to believe that babies are able to see/sense presence of things that we can’t, and these would include fairies and angels as well. :)
It is true! Both my children could see the "thing" when they were 1-2 years old especially during 7th month. My girl would stare at a particular spot and follow the "thing". I had to say some prayers before my girl's eyes followed the "thing" out of the windows and she never stare at the same place anymore. My boy at 1.5 years old pointed at a dark corner and called "po po". Initially we didnt think much but he kept pointing and calling the same place almost every night for a good 4 days till we realised sthg might be there. We had to say some prayers for it to be gone. So I believe young children especially those who can't talk much, can really see sthg.