In v3.0, we've documented that the maximum bitmap size is 4094x4094. We're changing the max size to 2048x2048. You'll also notice that the scroll example now refers to a VeryBigPng.png file on our website that now conforms to the new max size (the file shipped with the SDK does not yet conform).
The current v3.0 firmware build does not enforce the new restriction, but future builds will.
--Kevin