In the UpdMexico.zip there are three files:

1) Menuscrn.bmp is the map menu with new picture

2) Scnscr.bmp is the scenario selection map with new picture

3) bg_start.exe start the menu with new caption

These files must be copied in the installation library
of "us-mexican war".
Attention for the bg_start.exe : these file needs that the modules 
of "us-mexican war" will 
     a) Bv  -> Buena Vista
     b) Ch  -> Churubusco
     c) Mnr -> Monterrey
     d) Pa  -> Palo Alto
     e) Rp  -> Resaca de la Palma 

(My installation es. C:\Mexico\Bv; C:\Mexico\Ch; C:\Mexico\Mnr;
                     C:\Mexico\Pa; C:\Mexico\Rp)

Saluti by Sergio Chirico from Naples (Italy) 