diff --git a/lib/jpeg-lum.cc b/lib/jpeg-lum.cc
index 67e3fbc..b2e2716 100644
--- a/lib/jpeg-lum.cc
+++ b/lib/jpeg-lum.cc
@@ -82,7 +82,8 @@ int read_jpeg_file(char *filename)
   struct jpeg_error_mgr jerr;
   JSAMPROW row_pointer[1];
   FILE *infile = fopen(filename, "rb");
-  int i = 0, component = 0;
+  unsigned int i = 0;
+  int component = 0;
   if (!infile) {
       printf("Error opening jpeg file %s\n!", filename);
       return -1;