dcpomatic::Rect<int> all (images.front().position, images.front().image->size().width, images.front().image->size().height);
for (list<PositionImage>::const_iterator i = images.begin(); i != images.end(); ++i) {
all.extend (dcpomatic::Rect<int> (i->position, i->image->size().width, i->image->size().height));
dcpomatic::Rect<int> all (images.front().position, images.front().image->size().width, images.front().image->size().height);
for (list<PositionImage>::const_iterator i = images.begin(); i != images.end(); ++i) {
all.extend (dcpomatic::Rect<int> (i->position, i->image->size().width, i->image->size().height));