Alice Titzova of the PR agency 2media says the photos, stolen late Monday, were to be on display starting May 30 at the Prague Castle.
Titzova says mannequins and display cases which were part of the exhibition also disappeared. There was no word Wednesday whether the exhibition will be delayed or canceled.
The collection of various items including Monroe's dresses, shoes, photographs and diaries was assembled by curators at the Salvatore Ferragamo museum in Florence, Italy last year to mark the 50th anniversary of Monroe's death.
After Prague, the exhibition was to be moved to Tokyo.