rcbasic_pkg - HOW TO CHOOSE AN ICON ?

I wanted to create a WEB version of the game, but nothing is showing up in the icon selection window. What format should this icon be in?
...
I make PNG, and...:

F:\rcpkg_win>set PATH=F:\rcpkg_win\assets\rcbasic\rcbasic_32;C:\Windows\system32

;C:\Windows;C:\Windows\System32\Wbem;C:\Windows\System32\WindowsPowerShell\v1.0\





F:\rcpkg_win>cd assets



F:\rcpkg_win\assets>rcbasic main.cbc

WEB PRG_NAME$ = ZX_RAJD

WEB PRG_LOCATION$ = F:\rcbasic_win_313\ZXRAJD

WEB DST_LOCATION$ = F:\rcbasic_win_313\ZXRW\ZX_RAJD_web

ERROR: Could not make directory

Starting Emscripten Initial Setup....



'git' is not recognized as an internal or external command,

operable program or batch file.

Error: Could not change directory

'emsdk' is not recognized as an internal or external command,

operable program or batch file.