The format of this file is special, in that it can be read back into the same or another Squeak image to recreate those same classes and methods in a new environment. Note that the changes-file record of all your program edits uses the same fileOut format, so a ChangeList can browse the change history of any Squeak session. This can be easly invoked through the FileList 'browse changes' option. This allows you to fairly easily make a fileOut of just the most recent versions of a bunch of related changes that constitute your work on that project. ChangeSorters allow one to organize all system changes into a number of independent ChangeSets.
Projects offer a natural way of organizing related work, windows and changeSets.
Then in any folder with images for version X, put an alias of the VM for version X, and drag your image onto the VM alias to start it.