Terrorist groups now routinely use social media as a way to trumpet their atrocities -- but experts say the insurgent group sweeping Iraq is posting bloody images and videos in a manner that's extreme even for the most brutal militants.
The most recent horror came this weekend, when the Islamic State in Iraq and al-Sham (ISIS) posted photos in an online forum that appear to show the group massacring dozens of Iraqi government soldiers. (NBC News has not confirmed the authenticity of the photos, but an Iraqi military spokesperson told the Associated Press he believes the photos are real.)
Experts say the barrage of disturbing images is in line with ISIS' devastating and violent campaign thus far, in which the group has overtaken several Iraqi cities in its bid to take control of the country.
"ISIS is even more brutal than most, and their media output is no exception," Ghaffar Hussain, managing director at anti-extremist think tank Quilliam Foundation, told NBC News. "They're a bit mad to post video and photo of executions. But it's their way of showing they're more daring, more extreme, than anyone else."
On a basic level, ISIS uses social media in the same way extremist groups including Nigeria's Boko Haram and Somalia's Al-Shabaab do -- to control the narrative, boost morale, attract new supporters and demoralize their enemies.
But what sets ISIS apart is the volume of media they release on both private and public networks like Twitter and YouTube -- and the relentlessly graphic nature of the images.
"ISIS is nearly unparalleled in their extreme measure on every level, from the violence itself to the broadcasting of that violence," said Christopher Anzalone, a doctoral student at McGill University's Institute of Islamic Studies.
ISIS' media approach is more brutal because it's simply "more" of just about everything when compared to other militant groups, Anzalone said.
With a reported $2 billion war chest, ISIS is unusually well funded. Its relatively large force of 10,000 relies on more foreign fighters than most. And, perhaps most infamously, the group is too extreme even for Al-Qaeda.
That's why ISIS posts executions and other graphic images at a steady rate, while other extremist groups do so to send a special message, Anzalone said. Usually the group's postings are to offer a form of proof, he added, like to rebut a media report saying the group has exaggerated a certain attack.
By contrast, ISIS' steady drumbeat of violent imagery is a key tactic for the group -- especially in light of its rivalry with Al-Qaeda.
"By underlining a sense of constant progress and success, ISIS can challenge the viability and value of rival movements," Charles Lister, a terrorism analyst currently serving as a visiting fellow at the nonprofit Brookings Institute's Doha Center, told NBC News in an email.
ISIS's social media posts are "slick," Lister said, and "their intense content and frequency also give the sense of a tightly organized group capable of serious things."
Keeping up those appearances, especially in postings to a wide audience, is especially important for ISIS at this point in its short history, said Evan Kohlmann, the CIO of security firm Flashpoint Global Partners and a terrorism analyst for NBC News.
ISIS had been posting most of its core messaging to Al-Qaeda forums like Al-Fidaa and Shamukh, Kohlmann said, but sentiment shifted in February after a statement attributed to the Al-Qaeda leader denied any ties with ISIS.
"That's the challenge with social media: it works great when everyone is on the same page," Kohlmann said. "The membership on these Al-Qaeda sites is now divided, and what used to be a safe place for ISIS is now being used for messages against them too."
Public sites like Twitter won't ever become the main repository for the meat of ISIS' plans, Kohlmann said, but they do offer the group a better chance to control how they are perceived.
Twitter has appeared to suspend some ISIS-linked accounts, but the company declined to comment beyond pointing to its terms of service banning violence and unlawful use of the platform. Facebook and YouTube-owner Google did not reply to a request for comment.
Lister, the Brookings fellow, said ISIS' full-scale media approach particularly helped the group recruit fighters both home and abroad -- an attractive prospect for other militant groups, as they depend on support and manpower.
"The scale and relative professionalism of ISIS' management of social media and other PR platforms has been far superior..." Lister said. "I'd expect these groups to eventually follow ISIS' example."