diff --git a/tools/Makefile b/tools/Makefile
index 40a352e..6473fa1 100644
--- a/tools/Makefile
+++ b/tools/Makefile
@@ -36,7 +36,7 @@ mkfimg:		mkfimg.c  $(DEPS)
 	gcc $(COPT) $< ../libfloatimg.a -lm -o $@
 
 fimgops:		fimgops.c  $(DEPS)
-	gcc $(COPT) $< ../libfloatimg.a -o $@
+	gcc $(COPT) $< ../libfloatimg.a -lm -o $@
 
 fimgfx:		fimgfx.c  $(DEPS)
 	gcc $(COPT) $< ../libfloatimg.a 		\
diff --git a/tools/fimgops.c b/tools/fimgops.c
index 5182ba2..6be390d 100644
--- a/tools/fimgops.c
+++ b/tools/fimgops.c
@@ -66,6 +66,7 @@ static void help(int lj)
 
 puts("usage:\n\tfimgops [options] A.fimg B.fimg operator D.fimg");
 puts("options:");
+puts("\t-a\t\texport absolute value");
 // puts("\t-g              convert output to gray");
 printf("\t-k N.N\t\tset float value (def=%.3f)\n", global_fvalue);
 puts("\t-v\t\tincrease verbosity");
@@ -107,13 +108,15 @@ return foo;
 int main(int argc, char *argv[])
 {
 int		foo, opt, action;
+int		absolute = 0;
 char		*operator;
 FloatImg	srcA, srcB, dest;
 
 global_fvalue = 0.5;
 
-while ((opt = getopt(argc, argv, "hk:v")) != -1) {
+while ((opt = getopt(argc, argv, "ahk:v")) != -1) {
 	switch(opt) {
+		case 'a':	absolute = 1;			break;
 		case 'g':					break;
 		case 'h':	help(0);			break;
 		case 'k':	global_fvalue = atof(optarg);	break;
@@ -182,6 +185,11 @@ if (foo) {
 					operator, foo);
 	}
 
+if (absolute) {
+	if (verbosity) fprintf(stderr, "compute abs of %p\n", &dest);
+	fimg_absolute(&dest);
+	}
+
 foo = fimg_dump_to_file(&dest, argv[optind+3], 0);
 if (foo) {
 	fprintf(stderr, "dumping datas to file give us a %d\n", foo);