Sorry about the late response -- somehow I didn't get a notification on here.
More than likely it's just not finding the image if it takes longer than 30 seconds to display. It's probably throwing a null pointer exception (meaning it can't find the exact image in the data folder) but since the Python mode is a little behind the vanilla (Java) mode, it's not explicitly saying so.
If you can somehow get the sketch or code over to me, I'd love to be able to solve this one. Thanks again for your patience!