It is really just a matter of renaming the units.
First of all you should backup the original Graphics folder
Say for example that you wanted that the land units using the pic named "Unit_ROM_Hastati1.png" used instead the pic "Unit_ROM_Hastati4.png". You just rename the "Unit_ROM_Hastati4" as "Unit_ROM_Hastati1", deleting or giving other name to the original "Hastati1".
Beware though, that land units are represented in game by 3 different kind of pictures:
- the ones in Graphics\Units\Land Units (mentioned above)
- the ones in Graphics\Armies&Fleets1\Land Armies
- and finnally the ones in Graphics\Portraits\Land Portraits
Meaning, if you change one, you must make the corresponding change, if available, in all, to keep coherence between the pictures sown respectively in the unit roster in the lower part of the screen, the graphics on the map armies and the pictures on the element panels.
EDIT: after making changes, you have to delete cached files -
Units.Cached and
Models.Cached (located in the respective Units and Models folders) if not, no change takes place
Happy modding
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