When this sort of question comes up, it's usually a request for beyond a similar replacement. https://www.google.com/search?q=Picasa+3 finds it's still out there for download but who knows if it works today.
Invariably any title you offer you find the requester write it's not similar.
Google like this for alternatives then test till you find your new app: https://www.google.com/search?q=Picasa+3+Alternatives
what's a similar replacement for Picasa 3?