You are quite right. IrfanView is freeware for non-commercial use.
Current version 3.80
Links to some older versions:
Vers. 3.10
ftp://ftp.wiwi.uni-marburg.de/pub/wimm/to...cs/iview310.exe
Vers. 3.17
ftp://ftp.iif.hu/.ftp1/ftp.winsite.com/pu...op/iview317.exe
Vers. 3.20
ftp://ftp.iif.hu/.ftp1/ftp.winsite.com/pu...op/iview320.exe
Vers. 3.25
ftp://ftp.futurenet.co.uk/pub/pcformat/iview325.exe
Vers. 3.30
http://click.alltheweb.com/go2/2/atw/1cBB9...tg/iview330.exe
Vers. 3.33
http://click.alltheweb.com/go2/2/atw/1cD76...sf/iview333.exe
Vers. 3.36
ftp://ftp.nwg.ru/SoftWare/Graphics/IrfanV...ew/iview336.exe (very slow connection)
Vers. 3.60
ftp://ftp.au.ac.th/oldtucows/files2/iview360.exe
http://ftp.pu.edu.tw/cpatch/graphutil/irfa...ce/iview360.exe
Vers. 3.61
http://click.alltheweb.com/go2/2/atw/1c23A...ph/iview361.exe
ftp://ftp.cnl.salk.edu/pub/bryan/iview361.exe
ftp://ftp.sc.ru/pub/winstuff/Graph/iview361.exe
ftp://ftp.jcu.cz/utils/mm/irfanview/iview361.exe
ftp://ftp.prolink.de/pub/win9x/tools/iview361.exe
Vers. 3.70
ftp://ftp.iptelecom.net.ua/pub/win32.stuf...an/iview370.exe
http://ftp.pu.edu.tw/cpatch/graphutil/irfa...ce/iview370.exe
ftp://ftp.uakom.sk/pub/mirrors/sac/graph/iview370.exe
Vers. 3.75
ftp://ftp.biostat.wisc.edu/pub/jelewis/Ir...75/iview375.exe
ftp://ftp.tuke.sk/.mnt3/tucows/windows/fi...s2/iview375.exe
ftp://ftp.labyrinth.net.au/pub/tucows/fil...s2/iview375.exe
ftp://ftp.euro.net/pub/tucows/files2/iview375.exe
http://ftp.pu.edu.tw/cpatch/graphutil/irfa...ce/iview375.exe