gistfile1.cpp

	string allowed_extensions[5] = {".gif", ".jpg", ".png", ".bmp", ".pbb"};
	
	bool checkImage(string file){
		string extension = getExtension(file);
		for(int i = 0 ; i < 5 ; i ++ )
			if(allowed_extensions[i] == extension)
				return true;
  		return false;
	}
	
	string getExtension(string file){
		  int loc = file.find_last_of('.');
		  if(loc > -1){
		    return file.substr(loc);
		  }
		  return "";
	}