The 2017 and earlier editions of Bentley Map provide the ability to reference a Bentley Map Mobile redline (.markupdb) file, but do not support access to the embedded media.
In 2018 there are plans to release a new "Bentley Map Mobile - Markup Explorer" that will run inside a Bentley Map session as well as outside, as a Windows standalone application. It will not only provide access to the embedded media, but will add bi-directional search and geo-locate functionality for the .markupdb vector redline and embedded media data.
For now, a temporary solution for media file viewing on a desktop would be installing and using Bentley Map Mobile for Windows on a Windows desktop computer.
Bentley Map Mobile for Windows is available in the Bentley SELECT Software Fulfillment Center for 64-bit Windows 7, 8, and 10 desktops, notebooks, and touch-enabled tablet devices.
Link for reference: https://www.bentley.com/en/products/product-line/asset-performance/bentley-map-mobile
Related Forum Threads:https://communities.bentley.com/products/geospatial/desktop/f/bentley-map-forum/143766/redline-photo-from-bentley-map-mobile
https://communities.bentley.com/products/mobile_apps/f/information-mobility-forum/136793/markupdb-files