Hi, I have Zorin 15.3 on my laptop. How to instal PICASA (Google)?
That is a Windows application. In order to run it in Zorin, you would need WINE that can run Windows Software.
Alternatively, you can run a copy of Windows in VirtualBox.
If you would like to install WINE, you can click the picasa installer and follow the prompts.
Or in terminal:
sudo apt-get install zorin-windows-app-support