GUACAMOLE-307: The "size" instruction can also apply to buffers, not just layers.
diff --git a/src/guacenc/instruction-size.c b/src/guacenc/instruction-size.c
index 67c1e16..eb2a29d 100644
--- a/src/guacenc/instruction-size.c
+++ b/src/guacenc/instruction-size.c
@@ -38,13 +38,13 @@
     int width = atoi(argv[1]);
     int height = atoi(argv[2]);
 
-    /* Retrieve requested layer */
-    guacenc_layer* layer = guacenc_display_get_layer(display, index);
-    if (layer == NULL)
+    /* Retrieve requested layer/buffer */
+    guacenc_buffer* buffer = guacenc_display_get_related_buffer(display, index);
+    if (buffer == NULL)
         return 1;
 
-    /* Resize layer */
-    return guacenc_buffer_resize(layer->buffer, width, height);
+    /* Resize layer/buffer */
+    return guacenc_buffer_resize(buffer, width, height);
 
 }