diff --git a/src/bin/jp2/opj_dump.c b/src/bin/jp2/opj_dump.c
index a1252b5e..c12eb032 100644
--- a/src/bin/jp2/opj_dump.c
+++ b/src/bin/jp2/opj_dump.c
@@ -492,7 +492,8 @@ int main(int argc, char *argv[])
     opj_codestream_info_v2_t* cstr_info = NULL;
     opj_codestream_index_t* cstr_index = NULL;
 
-    unsigned int num_images, imageno;
+    unsigned int num_images;
+    OPJ_INT32 imageno;
     img_fol_t img_fol;
     dircnt_t *dirptr = NULL;