Some, I suppose were there before but, I've only noticed the others recently. ( the open doorway, arch without an arch)was done about a year ago! But, would these cracks only appear in other rooms? I've noticed some of the mouldings around some windows & doorways (where the paint has been for years) starting to have lines at their joints. There is only one that seems to be getting bigger though it did start earlier than last year anyway. Would putting a load of dry wall sheets in the attic also create these?