diff --git a/lib/operators.c b/lib/operators.c
index 12cdc3a..1c2b313 100644
--- a/lib/operators.c
+++ b/lib/operators.c
@@ -27,7 +27,9 @@ int		idx, nbpixels;
 fprintf(stderr, ">>> %s ( %p %p %p )\n", __func__, a, b, d);
 #endif
 
-if (3 != a->type || 3 != b->type || 3 != d->type) {
+if (FIMG_TYPE_RGB != a->type ||
+	FIMG_TYPE_RGB != b->type ||
+	FIMG_TYPE_RGB != d->type) {
 	fprintf(stderr, "%s : got a bad type fimg\n", __func__);
 	return -8;
 	} 
@@ -54,7 +56,7 @@ int		idx, nbpixels;
 fprintf(stderr, ">>> %s ( %p %p )\n", __func__, a, b);
 #endif
 
-if (3 != a->type || 3 != b->type) {
+if (FIMG_TYPE_RGB != a->type || FIMG_TYPE_RGB != b->type) {
 	fprintf(stderr, "%s : got a bad type fimg\n", __func__);
 	return -8;
 	}
@@ -81,7 +83,9 @@ int		idx, nbpixels;
 fprintf(stderr, ">>> %s ( %p %p %p )\n", __func__, a, b, d);
 #endif
 
-if (3 != a->type || 3 != b->type || 3 != d->type) {
+if (FIMG_TYPE_RGB != a->type ||
+	FIMG_TYPE_RGB != b->type ||
+	FIMG_TYPE_RGB != d->type) {
 	fprintf(stderr, "%s : got a bad type fimg\n", __func__);
 	return -8;
 	}
@@ -111,7 +115,7 @@ int		idx, nbpixels;
 fprintf(stderr, ">>> %s ( %p %p )\n", __func__, a, b);
 #endif
 
-if (3 != a->type || 3 != b->type) {
+if (FIMG_TYPE_RGB != a->type || FIMG_TYPE_RGB != b->type) {
 	fprintf(stderr, "%s : got a bad type fimg\n", __func__);
 	return -8;
 	}
@@ -124,6 +128,7 @@ for (idx=0; idx<nbpixels; idx++) {
 	b->B[idx] *= a->B[idx];
 	}
 
+return 0;
 }
 /* ---------------------------------------------------------------- */
 /*
@@ -137,7 +142,8 @@ int		idx, nbpixels;
 fprintf(stderr, ">>> %s ( %p %p %p )\n", __func__, a, b, d);
 #endif
 
-if (3 != a->type || 3 != b->type || 3 != d->type) {
+if (FIMG_TYPE_RGB != a->type || FIMG_TYPE_RGB != b->type ||
+		FIMG_TYPE_RGB != d->type) {
 	fprintf(stderr, "%s : got a bad type fimg\n", __func__);
 	return -8;
 	} 
@@ -161,7 +167,8 @@ int		idx, nbiter;
 fprintf(stderr, ">>> %s ( %p %p %p )\n", __func__, a, b, d);
 #endif
 
-if (3 != a->type || 3 != b->type || 3 != d->type) {
+if (FIMG_TYPE_RGB != a->type || FIMG_TYPE_RGB != b->type ||
+		FIMG_TYPE_RGB != d->type) {
 	fprintf(stderr, "%s : got a bad type fimg\n", __func__);
 	return -8;
 	}
@@ -186,7 +193,8 @@ int		idx, nbiter;
 fprintf(stderr, ">>> %s ( %p %p %p )\n", __func__, a, b, d);
 #endif
 
-if (3 != a->type || 3 != b->type || 3 != d->type) {
+if (FIMG_TYPE_RGB != a->type || FIMG_TYPE_RGB != b->type ||
+		FIMG_TYPE_RGB != d->type) {
 	fprintf(stderr, "%s : got a bad type fimg\n", __func__);
 	return -8;
 	}