The biggest resource file I know is Casus Belli's Edited Resource Compilation: http://forums.civfanatics.com/showthread.php?t=59068 He has 24 resource files in a row. From his "readme" text: The size or capacity of the resource sheets is not as important as the sequence of the icons. Civilization has the ability to easily read up to 999 resource icons on a pcx file. The number of icon slots in a row is not restricted to six and can be any manageable number. Likewise, the number of rows on a sheet is not restricted and an original sheet could be in practically any configuration (i.e. 6x6, 12x12, 24x36, etc.). So long as the sheet is labeled as resources.pcx and is located in place of the original file it can be used. However, for some as yet unexplained reason the maximum size replacement for the resources_shadows.pcx is a 6x11 (66 shadow icon) pcx sheet. If anything larger than this is used it causes the game to crash in Random games. This problem does not occur when the original resources.pcx is replaced with the 24x60 (1440) size icon sheet, but the shadows are not avilable. I attache a "cleaned up" version of this resource file.