Update 5/18/11 - Finally I had the time to update the post. I now have a working Google Goggles API set. In case you are wondering what changed: The protobuffer number a has changed from x + 401 to x + 32, where x is the image size. Also, there are trailing bytes that you need to send after the image byte array when posting the photo. All of this information is detailed in the post - just copy the