gnu: r-png: Move to (gnu packages cran).

* gnu/packages/image.scm (r-png): Move from here...
* gnu/packages/cran.scm (r-png): ...to here.

gnu/packages/cran.scm

@@ -13611,6 +13611,29 @@ principal component analysis, correspondence analysis, spectral map
 analysis.")
     (license license:gpl2+)))
 
+(define-public r-png
+  (package
+    (name "r-png")
+    (version "0.1-7")
+    (source (origin
+              (method url-fetch)
+              (uri (cran-uri "png" version))
+              (sha256
+               (base32
+                "0g2mcp55lvvpx4kd3mn225mpbxqcq73wy5qx8b4lyf04iybgysg2"))))
+    (build-system r-build-system)
+    (inputs
+     `(("libpng" ,libpng)
+       ("zlib" ,zlib)))
+    (home-page "http://www.rforge.net/png/")
+    (synopsis "Read and write PNG images")
+    (description
+     "This package provides an easy and simple way to read, write and display
+bitmap images stored in the PNG format.  It can read and write both files and
+in-memory raw vectors.")
+    ;; Any of these GPL versions.
+    (license (list license:gpl2 license:gpl3))))
+
 (define-public r-ggcorrplot
   (package
     (name "r-ggcorrplot")

gnu/packages/image.scm

@@ -198,29 +198,6 @@ APNG patch provides APNG support to libpng.")
         (base32
          "1izw9ybm27llk8531w6h4jp4rk2rxy2s9vil16nwik5dp0amyqxl"))))))
 
-(define-public r-png
-  (package
-    (name "r-png")
-    (version "0.1-7")
-    (source (origin
-              (method url-fetch)
-              (uri (cran-uri "png" version))
-              (sha256
-               (base32
-                "0g2mcp55lvvpx4kd3mn225mpbxqcq73wy5qx8b4lyf04iybgysg2"))))
-    (build-system r-build-system)
-    (inputs
-     `(("libpng" ,libpng)
-       ("zlib" ,zlib)))
-    (home-page "http://www.rforge.net/png/")
-    (synopsis "Read and write PNG images")
-    (description
-     "This package provides an easy and simple way to read, write and display
-bitmap images stored in the PNG format.  It can read and write both files and
-in-memory raw vectors.")
-    ;; Any of these GPL versions.
-    (license (list license:gpl2 license:gpl3))))
-
 (define-public pngcrush
   (package
    (name "pngcrush")