diff --git a/src/ArgParser.cc b/src/ArgParser.cc
index fcbe232..39945ef 100644
--- a/src/ArgParser.cc
+++ b/src/ArgParser.cc
@@ -58,7 +58,7 @@ void ArgParser::parse(int argc, char ** argv) const
 {
     //prepare optstring and longopts
     vector<char> optstring;
-    optstring.reserve(arg_entries.size() + 1);
+    optstring.reserve(2*arg_entries.size() + 1);
     vector<struct option> longopts;
     longopts.reserve(arg_entries.size() + 1);
 
diff --git a/src/pdf2htmlEX.cc b/src/pdf2htmlEX.cc
index 1c6511e..6df9bc8 100644
--- a/src/pdf2htmlEX.cc
+++ b/src/pdf2htmlEX.cc
@@ -183,14 +183,19 @@ int main(int argc, char **argv)
 
             if(get_suffix(param.input_filename) == ".pdf")
             {
-                param.output_filename = s.substr(0, s.size() - 4);
-                if(!param.split_pages)
+                if(param.split_pages)
+                    param.output_filename = s.substr(0, s.size() - 4);
+                else
                     param.output_filename = s.substr(0, s.size() - 4) + ".html";
+
             }
             else
             {
-                if(!param.split_pages)
+                if(param.split_pages)
+                    param.output_filename = s;
+                else
                     param.output_filename = s + ".html";
+                
             }
         }
         if(param.css_filename == "")
diff --git a/src/util.cc b/src/util.cc
index ab2ac80..ed41550 100644
--- a/src/util.cc
+++ b/src/util.cc
@@ -7,6 +7,7 @@
  */
 
 #include <errno.h>
+#include <cctype>
 
 #include <GfxState.h>
 #include <GfxFont.h>
@@ -201,7 +202,12 @@ string get_suffix(const string & path)
     if(idx == string::npos)
         return "";
     else
-        return fn.substr(idx);
+    {
+        string s = fn.substr(idx);
+        for(auto iter = s.begin(); iter != s.end(); ++iter)
+            *iter = tolower(*iter);
+        return s;
+    }
 }
 
 } // namespace pdf2htmlEX