diff --git a/lib/alphachan.c b/lib/alphachan.c
index 0ceee38..c0febda 100644
--- a/lib/alphachan.c
+++ b/lib/alphachan.c
@@ -13,11 +13,17 @@ extern int verbosity;           /* must be declared around main() */
 /* ---------------------------------------------------------------- */
 int fimg_add_alpha_chan(FloatImg *img)
 {
+
+fprintf(stderr, ">>> %s ( %p )\n", __func__, img);
+
 return -4;
 }
 /* ---------------------------------------------------------------- */
 int fimg_kill_alpha_chan(FloatImg *img)
 {
+
+fprintf(stderr, ">>> %s ( %p )\n", __func__, img);
+
 return -4;
 }
 /* ---------------------------------------------------------------- */
diff --git a/lib/fimg-math.c b/lib/fimg-math.c
index de6799d..29cdb73 100644
--- a/lib/fimg-math.c
+++ b/lib/fimg-math.c
@@ -124,7 +124,7 @@ return 0;
  * can compute the maxima of a lot of pictures...
  */
 
-fimg_max_of_max(FloatImg *img, float maxes[3])
+int fimg_max_of_max(FloatImg *img, float maxes[3])
 {
 float		localmax[3];
 int		idx, surface;
@@ -426,7 +426,8 @@ if (fi->type != FIMG_TYPE_RGB) {
 	return;
 	}
 nbre = fi->width * fi->height;
-// fprintf(stderr, "%s: %d pixels\n", __func__, nbre);
+
+fprintf(stderr, "in %s, drand48() is %f\n", __func__, drand48());
 
 for (idx=0; idx<nbre; idx++) {
 	fi->R[idx] = drand48() * kmul;