(For Internet Explorer) Right Click on the thumbnail to show the context menu. Scroll and select Properties and copy the URL address up to “/” symbol before the “s160-c” characters. Paste the copied URL to the address bar and press enter. That should show you the original size of the photo from my Picasa Web Albums.

As for the Firefox Web Browser and Chrome, it’s almost the same process. Let me know if you’re successful.

Cheers!