Does this mean: many children turn to books without pictures? Or many children turn to books with pictures?
What the original sentence means is that many children don't like books without pictures - this means many children like books with pictures (e.g., comics). As children grow older, they lose interest in books without pictures.
Note that "turn to" is a phrasal verb meaning "to go to someone or something to get help with a difficult situation" (Cambridge)
"Turn aside" is a phrase.
From The Free Dictionary
1.To deflect something; to direct or divert something away. A noun or pronoun can be used between "turn" and "aside."
- Special shielding on the space shuttle's windows turns harmful solar radiation aside to protect the astronauts inside.
- The president turned aside questions about his involvement with the company and changed the subject to matters of foreign policy.
3.To reject or dismiss something.
- They turned aside my entreaties to reverse their decision.
- Unfortunately, we've had to turn a number of applications aside because the applicants did not follow the instructions correctly.
While no. 3 seems very relevant, it has an implied sense of "deciding" that something is "not important and not worth considering." Children are simple - they just don't like books without pictures (I don't think they make a conscious decision that those books are not important). You can of course say that "children reject books without pictures" - that seems to be very direct though (e.g., after skimming a few pages for pictures, a child throws away the book realizing there are no pictures and starts to throw a tantrum).
4.To divert someone or cause someone to deviate from some activity, course, or direction.
- Having kids turned me aside from my ambitions as a writer, but I don't feel any regrets about it.
- Don't let the promise of power or wealth turn you aside from your moral compass.
Also "turn something aside" is "to evade something."
For your case, I think no. 4 fits best.
The absence of pictures in books turns children aside from reading them.
It simply means that children don't like to read books without pictures. They lose interest quickly (if they have already started reading them) and tend to avoid them as they grow older.