diff --git a/floatimg.h b/floatimg.h
index 46a206fe..bee8dfc6 100644
--- a/floatimg.h
+++ b/floatimg.h
@@ -20,7 +20,7 @@
  *	https://git.tetalab.org/tTh/FloatImg
  */
 
-#define		FIMG_VERSION	(198)
+#define		FIMG_VERSION	(201)
 #define		RELEASE_NAME	("noname")
 
 /* XXX add a test for stdint.h / uint32_t XXX */
@@ -233,7 +233,7 @@ int fimg_qsort_rgb_b(FloatImg *psrc, FloatImg *pdst, int notused);
 
 /*	module funcs/equalize.c		*/
 int fimg_equalize_compute(FloatImg *src, void *vptr, float vmax);
-int fimg_equalize(FloatImg *src, float vmax);
+int fimg_equalize(FloatImg *src, double vmax);
 
 int fimg_mk_gray_from(FloatImg *src, FloatImg*dst, int k);
 int fimg_desaturate(FloatImg *src, FloatImg *dst, int notused);
@@ -285,6 +285,7 @@ int   fimg_meanvalues(FloatImg *head, float means[4]);
 int   fimg_to_gray(FloatImg *head);
 int   fimg_add_cste(FloatImg *fi, float value);
 int   fimg_mul_cste(FloatImg *fi, float value);
+int   fimg_div_cste(FloatImg *fi, float value);
 int   fimg_ajust_from_grab(FloatImg *fi, double maxima, int notused);
 int   fimg_absolute(FloatImg *fimg);
 void  fimg_drand48(FloatImg *fi, float kmul);
diff --git a/lib/fimg-math.c b/lib/fimg-math.c
index 1e24d53d..17b7baa5 100644
--- a/lib/fimg-math.c
+++ b/lib/fimg-math.c
@@ -296,6 +296,33 @@ if (fi->type == FIMG_TYPE_GRAY) {
 return 0;
 }
 /* ---------------------------------------------------------------- */
+/*				nouveau 17 septembre 2022 */
+int   fimg_div_cste(FloatImg *fi, float value)
+{
+int		nbre, idx;
+
+if ( (fi->type != FIMG_TYPE_RGB) && (fi->type != FIMG_TYPE_GRAY) ) {
+	fprintf(stderr, "%s : type %d invalide\n",
+				__func__, fi->type);
+	return -44;
+	}
+
+nbre = fi->width * fi->height;
+if (fi->type == FIMG_TYPE_RGB) {
+	for (idx=0; idx<nbre; idx++) {
+		fi->R[idx] /= value;
+		fi->G[idx] /= value;
+		fi->B[idx] /= value;
+		}
+	}
+if (fi->type == FIMG_TYPE_GRAY) {
+	for (idx=0; idx<nbre; idx++) {
+		fi->R[idx] /= value;
+		}
+	}
+return 0;
+}
+/* ---------------------------------------------------------------- */
 /*
  *	oh, please explain the usecase of this function !
  */
diff --git a/tools/cumulfimgs.c b/tools/cumulfimgs.c
index 26efa200..2fbac9ce 100644
--- a/tools/cumulfimgs.c
+++ b/tools/cumulfimgs.c
@@ -40,9 +40,10 @@ void help(int v)
 puts("");
 puts("$ cumulfimgs a.fimg b.fimg c-fimg ...");
 puts("cumulator options :");
-puts("\t-v\tincrease verbosity");
-puts("\t-o\tname of output file");
 puts("\t-g\tconvert to gray level");
+puts("\t-o\tname of output file");
+puts("\t-s\trescale end image");
+puts("\t-v\tincrease verbosity");
 puts("");
 if (verbosity) { puts("Xperiment"); fimg_print_version(v); }
 exit(0);
@@ -52,22 +53,25 @@ int main(int argc, char *argv[])
 {
 int		foo, idx;
 int		opt;
-int		compte = 0;
 
-int		to_gray = 0;
-int		experiment = 0;
-char		*output_file = "out.fimg";
+int		compte		= 0;
+int		to_gray		= 0;
+int		experiment	= 0;
+int		rescale		= 0;
+int		src_loaded	= 0;
+
+char		*output_file	= "out.fimg";
 FloatImg	accu, temp;
-int		src_loaded = 0;
 float		vals[6];
 
 g_width = g_height = 0;
 
-while ((opt = getopt(argc, argv, "gho:vx")) != -1) {
+while ((opt = getopt(argc, argv, "gho:svx")) != -1) {
 	switch(opt) {
 		case 'g':	to_gray = 1;			break;
 		case 'h':	help(1);			break;
 		case 'o':	output_file = optarg;		break;
+		case 's':	rescale = 1;			break;
 		case 'v':	verbosity++;			break;
 		case 'x':	experiment++;			break;
 		}
@@ -84,7 +88,7 @@ for (idx=optind; idx<argc; idx++) {
 #endif
 	foo = testfile(argv[idx]);
 	if (foo) {
-		fprintf(stderr, "testfile %s -> %d\n", argv[idx],foo);
+		fprintf(stderr, "testfile %s -> %d\n", argv[idx], foo);
 		exit(1);
 		}
 
@@ -104,11 +108,16 @@ for (idx=optind; idx<argc; idx++) {
 	compte++;
 	}
 
-/*		XXX */
+if (rescale) {
+	fprintf(stderr, "cumulfimg: count = %d\n", compte);
+	fimg_div_cste(&accu, (float)compte);
+	}
+
+/*	XXX 		*/
 if (experiment) {
 
-		}
-/*		XXX */
+	}
+/*	XXX 		*/
 
 
 if (to_gray) {