Bonjour Samj
i just uploaded a new 64bit version i was thinking to apply to that your new modified configuration files (and icons and splash)

the first splash should match the " NO_EXTRA" configuration , or in other word the "demarrer_gimp.bat" of the first version, 
and the first icon is also for that same config in all its lingustic variants 

The second spash is to start in .."PhotoComix" mode, as the second icon should correspond to that mode
and match the exe to call gimp in that config in the various languages

in the zip..i tried to save the icon as ico using gimp, not sure if went good,