A snapshot describes an asset at a particular point in time. This description is sufficient to reproduce the asset completely at that point in time. TACTIC has its own XML description language to completely define assets and their dependencies to other assets.
A snapshot can contain any number of files. For example, in a Flash production, a typical checkin will result in 4 files: a .fla (the flash file to work on), .swf (a viewable file), and 2 pngs which represent a small icon and a large viewable image.
Every time something is checked in, a new snapshot is created of the asset. Snapshots can reference other snapshots, which allows TACTIC to define dependencies to other assets or other snapshots of the same asset.