Index: image.R
===================================================================
--- image.R	(revision 53953)
+++ image.R	(working copy)
@@ -24,7 +24,8 @@
 		   ylim = range(y),
 		   col = heat.colors(12), add = FALSE,
 		   xaxs = "i", yaxs = "i", xlab, ylab,
-                   breaks, oldstyle=FALSE, ...)
+                   breaks, oldstyle=FALSE, 
+                   useRaster=FALSE, ...)
 {
     if (missing(z)) {
 	if (!missing(x)) {
@@ -97,5 +98,12 @@
     if (length(y) <= 1) y <- par("usr")[3:4]
     if (length(x) != nrow(z)+1 || length(y) != ncol(z)+1)
         stop("dimensions of z are not length(x)(-1) times length(y)(-1)")
-    .Internal(image(as.double(x), as.double(y), as.integer(zi), col))
+    if (useRaster) {
+      zc <- col[zi+1]
+      dim(zc) <- dim(z)
+      rasterImage(as.raster(zc),
+                            xlim[1],ylim[1],xlim[2],ylim[2],interpolate=FALSE)
+    } else {
+      .Internal(image(as.double(x), as.double(y), as.integer(zi), col))
+    }
 }