I did a little project which allow you to save a st script on your HDD in a preference folder (~/.pharo#{version} for unix based machine, not yet defined for windows) and run it each time an image is open.

You can also decide for each item if you want it to be run each time or only once.

I use it to set my author name, change the fonts, set some settings, add my password in some repo etc

The code is here: 

Gofer new

squeaksource: 'StartupPreferences';

package: 'StartupPreferences';

load.

You can have a look at StartupLoader class>>#example and StartupLoader class>>#example2

If you have comments or ideas (by example, what is the path for preferences on windows ? ^^), you're welcome :)

Ben