winapi - SDL Image Not Supported : cute2.png is not a PNG file, or PNG support is not available -

i trying tutorial, :

• http://lazyfoo.net/sdl_tutorials/lesson03/windows/msvsnet0508e/index.php
• http://lazyfoo.net/sdl_tutorials/lesson02/index.php

and tried load , display portable network graphics (.png) files in application through simple code snippet:

#include "sdl.h" #include "sdl_image.h" #include "sdl_ttf.h" #include "sdl_mixer.h"  #include <stdio.h> #include <string>  //the attributes of screen const int screen_width = 640; const int screen_height = 480; const int screen_bpp = 32;                //the surfaces used sdl_surface *background = null; sdl_surface *screen = null; sdl_surface *message = null;  sdl_surface *load_image( std::string filename )  {     //the image that's loaded     sdl_surface* loadedimage = null;      //the optimized image used     sdl_surface* optimizedimage = null;      sdl_rwops *rwop;     rwop=sdl_rwfromfile(filename.c_str(), "rb");     if(img_ispng(rwop))         printf("%s png file.\n", filename.c_str());     else         printf("%s not png file, or png support not available.\n", filename.c_str());      //load image using sdl_image     loadedimage = img_load( filename.c_str() );      //if image loaded     if( loadedimage != null )     {         //create optimized image         optimizedimage = sdl_displayformat( loadedimage );          //free old image         sdl_freesurface( loadedimage );     }      //return optimized image     return optimizedimage; }   void apply_surface(int x, int y, sdl_surface *source_surface, sdl_surface *destintion_surface) {     //make temporary rectangle hold offsets     sdl_rect rectangle;      //give offsets rectangle     rectangle.x = x;     rectangle.y = y;      //blit surface     sdl_blitsurface(source_surface, null, destintion_surface, &rectangle); }  int main(int argc, char** argv) {     //initialize sdl subsystems     if(sdl_init(sdl_init_everything) == -1)         return 1;      //set screen     screen = sdl_setvideomode(screen_width, screen_height, screen_bpp, sdl_swsurface);      //if there error in setting screen     if(screen == null)         return 1;      //set window caption     sdl_wm_setcaption("surface bliting", null);      //load images     background = load_image("cute2.png");     message = load_image("cute4.png");      //apply background screen     apply_surface(0, 0, background, screen);     apply_surface(320, 0, background, screen);     apply_surface(0, 240, background, screen);                   apply_surface(320, 240, background, screen);      //apply message screen      apply_surface( 180, 140, message, screen );          //update screen     if(sdl_flip(screen) == -1)         return 1;      sdl_delay(12000);      sdl_freesurface(background);     sdl_freesurface(message);      //quit sdl      sdl_quit();      return 0; } 

now within visual stdio 2008, application running quite nicely.

but when trying run .exe directly application:

e:\sdl_sample\sdl image extension libraries\release\"sdl image extension libraries.exe" 

the stdout.txt showing messages:

cute2.png not png file, or png support not available.
cute4.png not png file, or png support not available.

and window closes without displaying/rendering anything.

i don't understand how images loading when build/run application within visual studio 2008, when run .exe, images not loading, image files, dll , every thing same in location.

it appears working directory solution isn't same output directory. \release folder compiled executable output , doesn't seem contain dll files sdl_image looking load support png file format (probably libpng##.dll).

an easy fix copy dynamic link libraries depend on output directory, whatever is, when launch program, finds of them automatically.