In the Milindapanha, it is said that there are ten kinds of gifts that are improper and will lead the giver to ruin. These include giving alcohol, weapons, poisons, which seems logical, but also paintings “cittakamma” (Mil 6.3.1. about Vessantara).
Does anyone know the background and the reason for this?
Great question, I’m curious too! A friend once gave some of her artwork to a meditation centre as dana (she has a low income), and they returned it to her as inappropriate. I wonder if this sutta was the reason?
This is a quirky topic! 
I’m sure someone (like @REddison / @Brahmali) would know much more than I.
It’s not justt in Mil, though; in the Vinaya Parivāra, it is said:
pañca dānāni apuññāni puññasammatāni lokasmiṃ … cittakammadānaṃered meritorious in the world:
Pañca dānāni apuññāni puññasammatāni lokasmiṁ—
alcohol, entertainment, a woman, a bull, and a picture. —
majjadānaṁ, samajjadānaṁ, itthidānaṁ, usabhadānaṁ, cittakammadānaṁ.
However, the Vinaya commentary says making paintings/decorations in a monastery is perfectly allowable:
āvāsaṃ kāretvā tattha cittakammaṃ kāretuṃ vaṭṭati
“Having built a dwelling, it is allowable to have paintings made there.”
It then says the prohibited case is specifically paṭibhāna-cittakamma-dāna, a particular sort of representational painting.
Then the subcommentary explains the diffetence:
itthipurisasaṃyogādikaṃ kilesasamudācārahetukaṃ …
i.e. imagery such as a woman and man having sexual intercourse, which provokes the arising/activity of the defilements.
So, these were the tidbits I had found on the subject.
I’m sure all of this raises more questions than it answers! 
I’m curious as well.
This is off-topic with regard to the paintings issue, but while we’re here, the first line of this sutta(?) uses the word Bodhisats which I don’t recall ever seeing before. Is this the plural of Bodhisattva or something else?
‘Venerable Nāgasena, do all the Bodisats give away their wives and children, or was it only Vessantara the king who did so?’
The Milindapanha is not a sutta, but a later text in which the Greek king Milinda has a conversation with the Buddhist monk Nagasena. The translation in Suttacentral is an old one, from Rhys Davids, maybe that explains the curious form ‘Bodhisats’.
Thank you, that’s interessting! Maybe it was taken for granted at the time that most pictures/paintings were very sensual, and thus inappropriate for a monastery?
Yeah, I have the Questions of King Milinda book but haven’t looked at it in a decade. I tried to check the Pali but I didn’t look in the right place. Dogan knew how and informed me that it is indeed the plural. The quirky Rhys Davids translation makes sense. Thanks Jesse85!
Now back to the OP!
Very unlikely. It probably has more to do with the fact that paintings/pictures are a very common thing for people to give and there just aren’t enough walls. And many places in the west are trying to have a certain “vibe” and museum gallery usually isn’t it.
Besides similes, I can’t think of any physical motivational symbols, iconography, artistic expressions or adornment favorably spoken of in the suttas. I’m wondering what purpose or benefit to the N8FP would the Buddha have ascribed to a painting. Would a painting have been considered inessential or perhaps distracting? Did the Buddha approve or sanction these kinds of items for the Sangha?
Kd 16 details:
- The prohibition against pictures
At that time the monks from the group of six had pictures of women and men drawn in a dwelling. When people walking about the dwellings saw this, they complained and criticized them, “They’re just like householders who indulge in worldly pleasures!” They told the Buddha.
“You shouldn’t have pictures drawn of women and men. If you do, you commit an offense of wrong conduct. I allow you to make garland patterns, creeper patterns, shark-teeth patterns, and the fivefold pattern.”