Apple uses a "feature" of the jpeg specification that few other software developers pay attention to. It's a flag that says something like "rotation angle". If you rotate your ipad and take a picture, it doesn't actually rotate the picture, it just says it's rotated. Any other Apple product will then rotate it to display, but nobody else will. If you want everybody else to see it properly, take the picture in landscape format with the button on the right. Actually, that's what you have to do for the iPhone, but I'm pretty sure it would be the same on the iPad.