Additional pictures released show the group's fighters in their attack on the Quneitra crossing, one of the Syrian regime's last footholds in the Golan Heights. Other pictures allegedly display one of the group's senior members standing in front of the border.
Another picture shows a group of rebels, without clear identification, celebrating the takeover of the crossing near the Israeli side.
The website also published a video in which Syrian rebels are seen firing on a UN building in Quneitra. Earlier on Thursday, Syrian militants fighting with the Jabhat al-Nusra kidnapped 43 Fijian soldiers from the UN Disengagement Observer Force (UNDOF) in the Golan Heights.
Earlier this week, the Philippines announced they would be recalling their 331-strong peacekeeping force after a number of violent incidents. For example, last September some 21 Filipino UN peacekeepers were kidnapped by Syrian rebels, and after a week were handed safely over to Jordan.
Earlier on Thursday, Syrian forces hit the rebels with air strikes after Wednesday's violence wounded two Israelis.
During the fighting Wednesday, two Israelis were wounded by stray bullets and a mortar, a soldier and a civilian, both in the Golan Heights. Israel responded with artillery fire at two Syrian army positions, the Israeli military said on Wednesday.