Ya'alon has been at the center of much contention in recent days in light of his comments backing IDF Chief of Staff Gadi Eisenkot and many senior officials and officers in the defense establishment who came out against a Kfir Brigade soldier for shooting dead a terrorist who was already lying wounded on the ground.
The photos, showing the defense minister's face framed by a rifle's target, were posted on social media and passed on WhatsApp groups of Likud activists, calling for an "assassination" of Ya'alon's political career.
"After all kinds of fringe radical elements tried to portray me as the troubler of Israel, the next stage has come (that should not have surprised anyone) - the distribution of photos inciting against me," Ya'alon wrote on Facebook and Twitter.
"This won't do them any good. I have no intention of caving in or conceding the fight for the nature of the State of Israel and Israeli society. I will continue fighting for a just, sane and moral State of Israel. One that fights with an iron fist and determination against those who mean to cause it harm, while at the same time doesn't lose sight of its values or becomes apathetic."
Ya'alon went on to say that "this isn't about the right wing or the left wing - this is about our future and that of our children. This is about what country we aspire to live in: One that is part of the family of nations, Jewish and democratic, modern and tolerant, or a country that is declining towards dangerous and destructive paths. We must stand firm and uncompromising against the kind of harmful discourse that has taken over the country. This fight is more important and significant than anything else, and the sane forces in Israeli society must remain united to defeat it."
The defense minister concluded his post by saying that "I am fighting for the sane majority of Israeli citizens. That is why I will not give up, and will not be deterred by any threat."
Prime Minister Benjamin Netanyahu, the Likud party leader, condemned the photos, saying the distribution of such photos "is crossing a red line."
"A public debate must be conducted in a respectable and topical manner and has no room for this kind of incitement," Netayahu said in a statement.
Officials in the Likud party said Ya'alon's comments will come back to haunt him, adding that the defense minister will pay the price in the next party primary election for not backing the shooting soldier.
Ya'alon drew fire when he slammed those who are defending the soldier, saying at a Knesset speech: "What do you want: a brutalized military that lost its moral spine?"
He said the soldier is not a hero, but rather a soldier who transgressed. "This is a grave incident," he stressed. "It was important for us - the IDF chief, the defense minister and the prime minister - to immediately say how we view this incident. We're not like the other side. I'm proud of the fact the company commander pointed to this being an unusual incident."
Earlier this week, Ya'alon also sent a message to politicians backing the soldier. "The IDF chief, and not gang leaders, will determine the rules of engagement," he said.
The defense minister, who was speaking at an event in Herzliya, added: "I won't get into the criminal proceedings. I addressed the disciplinary proceedings that ended and were harsh because of the severity of the act, which is against the law, our values, and the rules of engagement. Not one of us has mentioned the word 'murder' and there's an attempt to use it for manipulation. The soldier was warned in the beginning of the investigation that the most serious charge he faces was murder, but later the suspicions changed to manslaughter."