The Long War Journal has covered the other new declared province of the Islamic State, "Wilayat Saynaa (Sinai)" here.
The images were disseminated on Twitter by Islamic State supporters after being posted elsewhere on the Internet. The jihadist group has taken to releasing its propaganda via its supporters on Twitter, as the majority of its official accounts are continuously being suspended by the social media site.
The pictures showcase the oath of allegiance (bayah in Arabic) to Abu Bakr al Baghdadi and the Islamic State. The photos then proceed to showcase a rather large parade of vehicles presumably belonging to the aforementioned Majlis Shura Shabaab al Islam--which has previously already given bayah to al Baghdadi. This parade likely happened in Dernah, as the Islamic State has no real operational capabilities outside of there.
As such, these photos are more than likely playing the propaganda role of trying to make it seem like the Islamic State has a large presence throughout Libya. While the Islamic State also released pictures showing "martyrs" from fighting in Benghazi, they are overshadowed in that city by Ansar al Sharia and their allies. Ansar al Sharia is a group heavily connected to al Qaeda that operates in both Benghazi and Dernah (among other cities). However, Ansar al Sharia, is not that influential in Dernah. It has also been reported that the Islamic State took responsibility for car bombs against the embassies of the UAE and Egypt in Tripoli, Libya. However, Abdullah bin Zayed al Nahyan, the UAE's foreign minister, has blamed Ansar al Sharia and Fajr Libya (Libya Dawn); the latter being an allied group to Ansar al Sharia that has taken over Tripoli.
In an interview @MaliWitness did with a member of Majlis Shura Shabaab al Islam, the member confirms that only his group swore bayah to the Islamic State inside Dernah. The member says that Ansar al Sharia and Abu Salim Martyrs Brigade, another group operating in Dernah, have not pledged bayah to al Baghdadi. As all three groups control various parts of Dernah, it is unlikely the entire city gave bayah to al Baghdadi. Press reports saying that the city belongs to the Islamic State are therefore not entirely true.
The pictures released by Wilayat al Barqa can be seen below: