[Newbies] Programatically keep image up to date

[itsme213]

What is/are the recommended way/s to retaining my image customizations 
(mostly MC packages loaded, but ideally other environment customizations 
like preferences, keyboard shortcuts, preferred browsers, etc.) when I 
replace my image?

I am currently thinking of having a MC package with
    MyImage class>>initialize
        self customizeImage

Where should I look when implementing #customizeImage? Installer? LPF? 
Elsewhere?

Thanks - Sophie