For example this tweet from someone anonymous received over 20,000 retweets already:
The only part of this that has any truth is the National Cultural Center, which was bombed last August (not last weekend) because it also housed Hamas offices. It also had a library but that it not what the tweeter is referring to.
A building that was meant to be the Palestine National Library was never completed. Instead, the partially-built structure became a Hamas training camp and tunnel hub, which was bombed last July.
The only Azhar Library I can find in Gaza is the library at Al Azhar University. It was never bombed.
Here's another made up story:
I have searched high and low for any Arabic or English news story that mentions Fatmah Hjazi. There were two protesters killed last Friday, none of them had her name. No stories in Arabic news about any girl shot in the head. I see a number of pictures of this girl holding a flag, but none of her injured (which would normally be featured prominently.)
But I found lots of other tweets that repeated the lie, often followed with tweets about how inhumane Israel is to do such a thing.
These Israel haters literally make things up. They lie as easily as they breathe. And the thousands of people who are so anxious to believe them are either idiots, antisemites or both.