diff --git a/main.cpp b/main.cpp
index 8261b16..803241c 100644
--- a/main.cpp
+++ b/main.cpp
@@ -197,7 +197,7 @@ parseArgs(int argc, char *argv[]) {
   int i = 1;
   int resx = -1;
   int resy = -1;
-  for ( ; i < argc; i++ ) {
+  for ( ; i + 1 < argc; i++ ) {
     if ( !strcmp("-w", argv[i]) ) {
       resx = atoi(argv[++i]);
     } else if ( !strcmp("-h", argv[i]) ) {
