This painting was written by Picasso.
vs.
This painting was drawn by Picasso.
I know the second sentence seems to be correct. What if the painting was drawn by a pencil? What if it was a child graffiti? Is it still unnatural to use "write"?
This painting was written by Picasso.
vs.
This painting was drawn by Picasso.
I know the second sentence seems to be correct. What if the painting was drawn by a pencil? What if it was a child graffiti? Is it still unnatural to use "write"?
Unlike in some languages, paintings are not "written". The verb "write" implies the production of text, not art.
So you need to say "This painting was painted by Picasso".
This is rather repetitive, so you can say.
This is a painting by Picasso.
Or even
This is a Picasso.
To mean the same thing.
First, let's clarify some meanings:
Now let's address your questions:
This painting was written by Picasso.
This is wrong, because a "painting" typically contains no or very little text.
This painting was drawn by Picasso.
This is possible, but if the work was made with paint, then "draw" would be somewhat unusual. We could instead say that it was "painted" or "produced" by Picasso.
What if the painting was drawn by a pencil?
In that case, it wouldn't really be a "painting" anymore, and "drawn" would clearly be correct. We use pencils to draw.
What if it was a child graffiti? Is it still unnatural to use "write"?
It depends. I prefer "draw" with graffiti (or "paint" if it's painted), but Google NGrams indicates that "paint" and "write" are most common:
I'd still recommend using "write" only if the graffiti contained actual text (words, numbers, etc.).