If you run "Squeak myImage.image script.st arg1 arg2 arg3", then script.st will be filed in as the image starts up.
arg1, arg2, and so on may be accessed with SystemDictionary>>getSystemAttribute:. The argument to getSystemAttribute: is an integer which determines what is returned:
0 - Virtual Machine name
1 - Image name
2 - Script file name
3 ... n - additional arguments