Oh dear. This is one of my pet niggles about the current state of affairs re various releases, ie, it's difficult, for me at least and I suspect others, to choose and stick to one image. A quick search of my top level Squeak directory gives me ~1G of image files! I'm partly to blame since during my experiment-by-loading-everything-in-sight sessions I will typically download and use the image that works/supports whatever particular package I'm investigating at that time. Consequently I have various experimental code scatter over many of these 32 images and you can guarantee that if I export a change-set it won't cleanly import into another image. Hopefully I will eventually reach the skill level that allows me to fix things on the fly in these situations but I have to say even when I reach that level I still won't look forward to doing it because it happens too often and would be a distraction from my whatever I'm doing (Squeak-wise). True it would provide good learning experience but for a newbie(ish) it sorely dents my motivation.
I not blaming you, Damien, or anyone else specifically for this but then the multitude of ways to load stuff into Squeak or update existing packages, not to mention the "Update" button, leaves me in total confusion about the best way to keep current without breaking things. Thoughts on this as well as ways to manage various unrelated bits of code are more than welcome!
PS: Downloading another image now my rant is over ;-)