My next gallary posting took about 12 hours to render. After the first hour I was forced to cancel and discovered another use of the area render. Export your half finished picture as a png. This will be transparent where the render did not reach. When you have time to continue, use the area render to pick up from where you finished last time, then export the rest of the picture. In most paint packages, open both pictures, then select the first one, with the top left corner rendered, and paste it into the second one. They should line up perfectly. Networked renders anyone? My final picture was stitched together out of seven fragments.