Researchers have been documenting how museums used social networks during the COVID‐19 global health emergency, however, to date there has been limited assessment of museums' uses of Instagram at that time. This article begins to address that gap with a case study of Philbrook Museum of Art's approach to that platform during the early months of the pandemic. We use a mixed‐method inquiry featuring social media analysis and a series of interviews with staff at the museum to analyze the museum's use of Instagram to maintain a presence within followers' lives during this intensely challenging period. To frame our analysis we introduce Gibbs et al.'s (Information, Communication & Society, 2015, 18, 255) concept of “platform vernacular” to digital heritage studies, trialing its use to critically analyze the combination of affordances, practices, and communicative conventions that Instagram convenes for the museum. We find this approach to be both theoretically and practically insightful, with the potential to inform more meaningful, authentic, and transparent interactions between institutions and users within social networks.