That was my first thought, ask Edgar whether the intention was for
image production.
And ask about the impact of such change onto every day update.
But it seems it has the merit of uncovring some ghost dependents bug.

2013/1/21 Chris Muller <asqueaker at gmail.com>:
> -10.  Updating the image is done under many use-cases, not just
> building an image.  There are many cases where you would not want this
> done.  Cleaning the image must be its own independent operation
> independent of other operations, especially the ones for _building_
> the image.
>
> On Mon, Jan 21, 2013 at 8:05 AM,  <commits at source.squeak.org> wrote:
>> Edgar J. De Cleene uploaded a new version of System to project The Inbox:
>> http://source.squeak.org/inbox/System-edc.512.mcz
>>
>> ==================== Summary ====================
>>
>> Name: System-edc.512
>> Author: edc
>> Time: 21 January 2013, 11:05:08.17 am
>> UUID: d7a321ce-cf99-4b7d-9c9f-12e0470672a7
>> Ancestors: System-fbs.511
>>
>> When you update from server , the resuting image is not cleaned and bigger as should be.
>>
>> =============== Diff against System-fbs.511 ===============
>>
>> Item was changed:
>>   ----- Method: Utilities class>>updateFromServer (in category 'fetching updates') -----
>>   updateFromServer
>>         "Update the image by loading all pending updates from the server."
>>         | config |
>>         "Flush all caches. If a previous download failed this is often helpful"
>>         MCFileBasedRepository flushAllCaches.
>>         config := MCMcmUpdater updateFromDefaultRepository.
>>         config ifNil: [^self inform: 'Unable to retrieve updates from remote repository.' translated].
>>         self setSystemVersionFromConfig: config.
>>         self inform: ('Update completed.
>> + Current update number: ' translated, SystemVersion current highestUpdate).
>> + self updateFromServerCleanup.!
>> - Current update number: ' translated, SystemVersion current highestUpdate).!
>>
>> Item was added:
>> + ----- Method: Utilities class>>updateFromServerCleanup (in category 'fetching updates') -----
>> + updateFromServerCleanup
>> +       MCFileBasedRepository flushAllCaches.
>> + MCDefinition clearInstances.
>> + 3 timesRepeat: [ Smalltalk garbageCollect].
>> + !
>>
>>
>