Well, the latest Arduino IDE version under Linux behaved exactly the same ...
I have noticed as well that the blink sketch compiles to different sizes under both Linux and Windows - I assume that this must be something to do with the toolchain / gcc-avr version.
It looks like my only solution to use these cameras is to program them under Windows! However, I'm not sure I'll be using them very much as they aren't very capable. They are OK if you need to take occasional still images (1 per minute at best), but the resolution isn't great and they are slow.
I'm still baffled by the difference though and would dearly love to figure it out!
Alex