Finding Family-tree of images

>
> I have a hibbit of saving new version of images when i feed unsecure about
> something. So i end up a lot of disk space taken by them. I felt it is time
> for me to clean up the redundance in my disk. I wanted to have a sense of
> family tree of the images.
>
> l := (FileStream fileNamed:'Squeak4.0-basic-pocketcube-morphic.changes')
> contents lines.
>
> s := l select: [:each| each beginsWith: '----SNAPSHOT----'].
>
> i := OrderedCollection new.
> (s collect: [:ea| ea substrings at: 7 ]) do: [:e|
>        (i includes: e) ifFalse: [i addLast: e.].
>        ].
> i
>
> Now i have images names in time order. But still i need to run this code on
> every images not listed in evaluated result.
>
> How do you handle this problem?
>