"This is a statement, symbolic of defiance," Pollack told The Washington Post. "The pursuit of sanctions relief is over. Nothing is made explicit here, but it starts to set new expectations about the coming course of policy for 2020."
North Koreans have suffered from international sanctions due to its nuclear program; the photos seem to show that North Korea will not bow to international pressure.
According to multiple reports, Kim Jong Un has visted Mt. Paektu prior to major announcements or policy decisions before. For example, a 2017 trip came just days after the North Korean military launched its largest-ever intercontinental ballistic missile.
Madden told Insider that the photo shoot most likely portends a military announcement of some kind, possibly that North Korea and China are announcing a long-term strategic aggreement. "A member of the Chinese Military Commission is in North Korea right now, and [talks are] going very, very, very well," he told Insider.
Madden told Insider that "North Korea in 2020 is either going to launch a rocket, or announce that they have attained the ability to perform sub-critical nuclear tests," and the photos could be in advance of such an announcement.
Whatever the announcement is, it's almost certainly not about making concessions to the US or any of its allies, Madden said.
"North Korea has massively regressed in the past few months," in terms of foreign policy "and I have no idea why," Madden noted.