diff --git a/install.sh b/install.sh
index 23c8525..d3d5010 100755
--- a/install.sh
+++ b/install.sh
@@ -3,7 +3,7 @@
 cp	libfloatimg.a 	/usr/local/lib
 cp	floatimg.h 	/usr/local/include
 
-cp	tools/mkfimg tools/fimg2pnm 	\
+cp	tools/mkfimg tools/fimg2pnm tools/fimgops 	\
 	tools/png2fimg tools/fimgstats			\
 	/usr/local/bin
 
diff --git a/tools/fimgops.c b/tools/fimgops.c
index bab7786..e3e17b5 100644
--- a/tools/fimgops.c
+++ b/tools/fimgops.c
@@ -9,7 +9,8 @@ int		verbosity;
 
 /* --------------------------------------------------------------------- */
 #define		OP_ADD		1
-#define		OP_MUL		2
+#define		OP_SUB		2
+#define		OP_MUL		4
 typedef struct {
 	int	code;
 	char	*op;
@@ -17,6 +18,7 @@ typedef struct {
 
 Opcode opcodes[] = {
 	{ OP_ADD,		"add"		},
+	{ OP_SUB,		"sub"		},
 	{ OP_MUL,		"mul"		},
 	{ 0,			NULL		}
 	};
@@ -28,13 +30,17 @@ for (optr = opcodes; optr->code; optr++) {
 	printf("\t%-20s %d\n", optr->op, optr->code); 
 	} 
 }
-static int look_opcodes(char *txt)
+static int look_opcode(char *txt)
 {
 Opcode *optr;
 
+#if DEBUG_LEVEL
+fprintf(stderr, ">>> %s ( '%s' )\n", __func__, txt);
+#endif
+
 for (optr = opcodes; optr->code; optr++) {
 	if (!strcmp(txt, optr->op)) {
-		printf("found %s as %d\n", optr->op, optr->code);
+		// printf("found %s as %d\n", optr->op, optr->code);
 		return optr->code;
 		}
 	} 
@@ -50,12 +56,33 @@ if (verbosity) fimg_print_version(1);
 exit(0);
 }
 /* --------------------------------------------------------------------- */
+int exec_operator(FloatImg *A, FloatImg *B, int action, FloatImg *D)
+{
+int	foo;
+
+switch (action)	{
+
+	case OP_ADD:
+		foo = fimg_add(A, B, D);		break;
+	case OP_SUB:
+		foo = fimg_sub(A, B, D);		break;
+	case OP_MUL:
+		foo = fimg_add(A, B, D);		break;
+	default:
+		foo = -99;				break;
+
+	}
+
+return foo;
+}
+/* --------------------------------------------------------------------- */
 int main(int argc, char *argv[])
 {
-int		foo, opt;
+int		foo, opt, action;
 float		fvalue;
+char		*operator;
 
-FloatImg	fimg;
+FloatImg	srcA, srcB, dest;
 
 while ((opt = getopt(argc, argv, "hk:v")) != -1) {
 	switch(opt) {
@@ -76,6 +103,53 @@ if (4 != argc-optind) {
 	exit(1);
 	}
 
+operator = argv[optind+2];
+action = look_opcode(operator);
+if (action < 0) {
+	fprintf(stderr, "%s : opcode '%s' unknow\n", argv[0], operator);
+	exit(1);
+	}
+
+/*
+ *	load the two source files, and check comatibility
+ */
+if ((foo=fimg_create_from_dump(argv[optind], &srcA))) {
+	fprintf(stderr, "read error on '%s' is %d\n", argv[optind], foo);
+	exit(2);
+	}
+if ((foo=fimg_create_from_dump(argv[optind+1], &srcB))) {
+	fprintf(stderr, "read error on '%s' is %d\n", argv[optind+1], foo);
+	exit(3);
+	}
+
+if (verbosity) {				/* please, debug me */
+	fimg_describe(&srcA, argv[optind]);
+	fimg_describe(&srcB, argv[optind+1]);
+	}
+
+foo = fimg_images_compatible(&srcA, &srcB);
+if (foo) {
+	fprintf(stderr, "images are not compatibles, %d\n", foo);
+	exit(4);
+	}
+
+/*
+ *	we can now create the resultant image, and going coredump...
+ */
+foo = fimg_create(&dest, srcA.width, srcA.height, srcA.type);
+// fimg_describe(&dest, "destination");
+
+foo = exec_operator(&srcA, &srcB, action, &dest);
+if (foo) {
+	fprintf(stderr, "operator exec give us a %d\n", foo);
+	}
+
+foo = fimg_dump_to_file(&dest, argv[optind+3], 0);
+if (foo) {
+	fprintf(stderr, "dumping datas to file give us a %d\n", foo);
+	}
+
+
 return 0;
 }
 /* --------------------------------------------------------------------- */