Even if there is only one picture, it is still a picture, so the question is still grammatically correct. It's just deliberately ambiguous. I am taking this stand.
Knocks over a statue and walks away with the stand
This comic makes me sad. Magritte is great, but I don't know where, "The Son of Man" is located. Every time I search the only thing I find is "Private Collection".
I highly encourage you to seek out the original paintings and other artistic mediums in museums when you have a chance. It's not about prestige, authenticity, or clout. It's about gazing upon relics that have somehow survived the test of time and gleaming a bit of the creator's intentions and skill. It's a human connection that can stretch the breadth of millennia.
Also I used to fix printers so now I have undying hatred of them. I buy quite a few art books though.
Edit: One thing photos, digital image files, and other means of reproduction of most paintings never seem to get right is the texture. Remember a painting is not flat, it's still a 3rd dimensional object. Painting techniques can layer paints giving them texture, it's a visual quality that is hard to appreciate when not in person.
And energy in turn derives from the sub-atomic level, which itself sits on top of the quantum, although some people say that it is all oscillations of n-branes... therefore do any words ever have any meaning, really, ever?:-P
It seems the word picture at the very least used to be used for paintings as well, so it's more that it's just an uncommon usage. Maybe the guy is a time traveler.
Or Pictures at an Exhibition (wikipaedia link) by Modest Mussorgsky?
(Especially the Emerson, Lake & Palmer version) (Youtube link)
In the UK at least, "Picture" is totally fine shorthand, even today, to refer to a flat 2D thing that might be put on a wall in a gallery, whether it be a painting, drawing, photograph etc. More formally it would tend towards being a figurative (rather than abstract) work.
