SCI Companion supports adding resources to your game, and extracting them from your game.
You can add a resource from external files by either browsing to them in a file dialog (File->AddResource), or by dropping them in from Windows Explorer. In the latter case, the name of the file is used to determine the resource number.
Resource files are named View.xxx, Pic.xxx, and so on, where xxx is a three digit number. They are the same files generated by and consumed by SCI Studio, and used as patches by the SCI engine.
To extract a resource, right click on the item and choose "Export to file".