diff --git a/wrlib/wraster.h b/wrlib/wraster.h
index 7933ea60..2c80ff97 100644
--- a/wrlib/wraster.h
+++ b/wrlib/wraster.h
@@ -190,7 +190,7 @@ enum RImageFormat {
  */
 typedef struct RImage {
     unsigned char *data;	       /* image data RGBA or RGB */
-    unsigned width, height;	       /* size of the image */
+    int width, height;	       /* size of the image */
     enum RImageFormat format;
     RColor background;		       /* background color */
 } RImage;