Basically G3 is looking for an image at least 8192 x 4096 pixels which contains a 360 degree x 180 degree (Equirectangular) view

More info ...

http://www.rcuniverse.com/forum/m_33...tm.htm#3381125

then there are lot more links here (photofield section) ...

http://www.knifeedge.com/forums/showthread.php?t=11067