Q: Why do you need access to my Google account?
A: You authorize app to upload your data into Picasa Web.
Q: Do you see or store my Google Password?
A: No, I don't. You give your password solely to Google and Google returns us authorization token that can be used for this app only and you can reject it anytime at http://accounts.google.com. Authorization token is like "single purpose password" for specific app and specific purpose. It can't be used for accessing anything else.
Q: What exactly do you do with access to my Google Account?
A: App reads names of your Picasa Albums and uploads picture to specified album. It DOES NOT read any picture from your Picasa albums nor reads your email address or any other personal information.