title: SDL2 Image to screen issue
body: <p>I've been on the hunt trying to figure out how to get this to execute properly. I've been having trouble finding good documentation on SDL (If anyone has a most necessary goto I would love to check it out).</p>
  
  <p>So, after finding out that <code>SDL_Flip</code> and <code>SDL_SetVideoMode</code> are extinct while amidst in Lazy Foo's tutorials and finding out it's all about windows now. I can't seem to get an image to the screen still. I'm completely new to SDL (obviously). So, everything compiles fine. I'm compiling in the source directory where the image.bmp is also located, but for some reason the image pointer returns <code>NULL</code> and I just get a blank screen when the program executes. </p>
  
  <p>One more thing. I get this error from <code>SDL_GetError</code>: "passed a NULL surface". Is that because for what ever reason the image is returning <code>NULL</code> or can't be opened?</p>
  
  <p>Here is the source:</p>
  
  <pre><code>#include "SDL2\SDL.h"
  #include &lt;stdio.h&gt;
  #include &lt;stdlib.h&gt;
  int main(int argc, char* args[]){
  
  SDL_Surface *image = NULL;
  SDL_Window *window = NULL;
  SDL_Surface *screen = NULL;
  
  SDL_Init(SDL_INIT_VIDEO );
  
  window = SDL_CreateWindow( "img.cc", SDL_WINDOWPOS_UNDEFINED, SDL_WINDOWPOS_UNDEFINED, 640, 480, 0);
  
  screen = SDL_GetWindowSurface(window);
  
  image = SDL_LoadBMP("image.bmp");
  
  SDL_BlitSurface( image, NULL, screen, NULL );
  
  SDL_FreeSurface( image );
  SDL_UpdateWindowSurface(window);
  if(SDL_GetError != NULL)
  {   
      fprintf(stdout,"SDL_GetError: %s\n",SDL_GetError());
  }
  if(image == NULL)
  {
      fprintf(stdout,"Image is NULL");
  }
  //Pause
  SDL_Delay( 2000 );
  
  //Free the loaded image
  SDL_DestroyWindow( window );
  
  //Quit SDL
  SDL_Quit();
  
  return 0;
  }
  </code></pre>