my security system found a virus in this software.
Picasa does not contain a virus! A virus is software which can replicate itself and usually does something nasty!
I think you may be referring to an outbound ping which Picasa actions upon installation, this is used as an install counter and contains no information about the computer where the installation has taken place - more details
hereIf you beleive this to be wrong, please tell me the name of the virus and the virus software you use so I can approach Google with your findings.
Thanks,
Andy Gee