If you think that this file contains a virus or another malware, please download a virus scanner.
If photo1.exe is using too much CPU or too much memory in your system, it is possible that your file has been infected with a virus. Installing an antivirus is recommended.
Not all processes can be uninstalled without the help of a 3rd party tool, especially malware. To see if it can be uninstalled, first go to Start > Control Panel > Add/Remove programs and select Picasa Photo Viewer from the list to remove the process photo1.exe from your computer.
You may try contacting Google Inc., the developer of photo1.exe and ask for more information.