This is the 4771st most frequent Russian word.
запостила
"Запостила" means "posted" (specifically, she posted something online).
The word "запостила" is used here in the past tense to describe the action of posting content online, specifically a photograph.
Она запостила фотографию на своей странице.
She posted a photograph on her page.
The word "запостила" is used here in an interrogative sentence, asking about the action of posting information online.
Почему ты запостила эту информацию без проверки?
Why did you post this information without verifying it?
In this conditional sentence, "запостила" is used to express a hypothetical past action of posting news.