The world's outrage over 40,000 dead Syrians (and climbing) has been kept at a low level. Already, Israel's acts to defend themselves from Palestinian rocket attacks on civilian targets in Israel are prompting more outrage in the Arab world. Let's remember three key facts as the fighting in Gaza continues and possibly escalates.
Remember that Hamas is trying to kill civilians. That is a war crime.
Remember that Israel is trying to destroy rockets and enemy fighters. Sometimes civilians will be accidentally killed. That is not a war crime.
Remember that the Palestinians will house military targets in or near civilians to protect them from Israeli attacks or for the propaganda bonus of dead Palestinians. That is a war crime by the Palestinians.
To recap, attempting to kill civilians, killing civilians, and deliberately placing civilians at risk to protect military assets or to gain propaganda talking points are war crimes.
Killing civilians accidentally while pursuing legitimate war aims is not a war crime. Mind you, that isn't a blanket get out of jail free card. Blowing up a school full of kids isn't legal just because you say you are trying to destroy a loaded rifle clip believed to be in a desk drawer in the basement.
UPDATE: Keeping these things in mind, ask yourself why the Palestinians would need to fake civilian casualties if the Israelis are truly just trying to kill civilians as a matter of policy?