When making an image of a rather big matrix, containing a lot of NA's and not that much real numbers, like in the following (rather simple) example M <- matrix(NA,1000,1000) M[,seq(1,1000,length.out=50)] <- 1 image(M) information (in this case: horizontal lines) is missing in the resulting image. This probably is because the vertical screen resolution is smaller than the number of rows in the matrix. Does anyone know of a general method (apart from the obvious and not really general methods of buying a bigger screen, zooming in on part of the matrix, and simply not making an image of such a big matrix) that causes the missing lines to be visualized? When I visualized the same matrix in Matlab (my sincere apologies to those considering this to be blasphemy), looking at a mesh plot from the top, all the lines were nicely visible, so it should be possible in some way... Regards, Tom Bloemberg