diff --git a/wrlib/gif.c b/wrlib/gif.c
index 1ad638a5..1242daaf 100644
--- a/wrlib/gif.c
+++ b/wrlib/gif.c
@@ -39,7 +39,7 @@ static int InterlacedJumps[] = { 8, 8, 4, 2 };
 /*
  * Partially based on code in gif2rgb from giflib, by Gershon Elber.
  */
-RImage *RLoadGIF(char *file, int index)
+RImage *RLoadGIF(const char *file, int index)
 {
 	RImage *image = NULL;
 	unsigned char *cptr;
diff --git a/wrlib/nxpm.c b/wrlib/nxpm.c
index 0574fd94..37a48e8a 100644
--- a/wrlib/nxpm.c
+++ b/wrlib/nxpm.c
@@ -228,7 +228,7 @@ RImage *RGetImageFromXPMData(RContext * context, char **data)
 	return NULL;
 }
 
-RImage *RLoadXPM(RContext * context, char *file)
+RImage *RLoadXPM(RContext * context, const char *file)
 {
 	RImage *image = NULL;
 	char line[LINEWIDTH + 1];