Delta DC-7 - smoke
Like the National DC-7B a few rows up, this is an old screenshot from Flight Simulator 2002, and does not have the resolution needed for a larger version of the image.  The simulator itself is capable of displaying up to 1600x1200 pixels, but the computers most of us had then were not very capable of displaying that detailed a picture while also giving us a screen refresh rate that was suitable for flying.  Most simulator people try to keep their frame rates above about 25 frames per second -- faster than that isn't much help because at that speed the display appears to be continuous anyway.  25 FPS and 100 look about the same to the human eye.

All that aside, this is arguably one of the prettiest schemes ever seen on a DC-7 and is certainly a favorite with many of us.  I believe it was shot at Asheville, NC.