diff --git a/README.md b/README.md
index 42bef8b..78fdd79 100644
--- a/README.md
+++ b/README.md
@@ -250,7 +250,8 @@ One of the possibly useful demo applications is an image viewer that
 reads all kinds of image formats, including animated gifs. It is not compiled
 by default, as you need to install the GraphicsMagick dependencies first:
 
-     sudo aptitude install libgraphicsmagick++-dev libwebp-dev
+     sudo apt-get update
+     sudo apt-get install libgraphicsmagick++-dev libwebp-dev
      make led-image-viewer
 
 Then, you can run it with any common image format, including animated gifs:
diff --git a/led-image-viewer.cc b/led-image-viewer.cc
index d0ea76f..c4af907 100644
--- a/led-image-viewer.cc
+++ b/led-image-viewer.cc
@@ -14,7 +14,7 @@
 // along with this program.  If not, see <http://gnu.org/licenses/gpl-2.0.txt>
 
 // To use this image viewer, first get image-magick development files
-// $ sudo aptitude install libmagick++-dev
+// $ sudo apt-get install libgraphicsmagick++-dev libwebp-dev
 //
 // Then compile with
 // $ make led-image-viewer