are "photographs" taken of a scene in SL. There is not currently a way to take snapshots using LSL. You can only take a snapshot with a client
computer to render the image. There isn't actually anything "there" in SL. It's just numbers that are turned into an image on the client.
However, even if you required a client present to do so, automated asset creation is not something the Lindens are eager to implement, as the load on the asset server would be tremendous. This is the same reason that we can only read notecards
A snapshot is also a specific inventory
item, with their own inventory folder and icon. Snapshots differ from textures
in that they are created by the snapshot tool within SL, rather than uploaded as a texture. By using snapshot-to-disk, then uploading the resulting image, you will get a texture item, not a snapshot.