Photos in Picasa Web Albums by default are automatically mapped to their geographical information based on their EXIF details.
This can be disabled if needed.
To do this :
Login to Picasa and access Settings (or by clicking on the gear icon on top right and selecting “Settings”).
From the “Privacy and Permissions” tab, remove the tick mark next to “Automatically map photos in Picasa Web Albums..”.
Finally, hit the “Save changes” button.