Self install versions have special start options for silent install
1) IrfanView:
iview392.exe /silent /folder="c:\test folder\irfanview" /desktop=1 /thumbs=1 /group=1 /allusers=0 /assoc=1

Options:
folder: destination folder; if not indicated: old IrfanView folder is used, if not found, the "Program Files" folder is used
desktop: create desktop shortcut; 0 = no, 1 = yes
thumbs: create desktop shortcut for thumbnails; 0 = no, 1 = yes
group: create group in Start menu; 0 = no, 1 = yes
allusers: desktop/group links are for all users; 0 = current user, 1 = all users
assoc: set file associations; 1 = images only, 2 = select all

2) PlugIns:
irfanview_plugins_392.exe /silent

3) Uninstall:
iv_uninstall.exe /silent

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