Code:

---

// A white pcx, probably 1280x960 so its big enough for any screensize
bmap white_flash = <white.pcx>;

bmap screen_shot_map = <emptypanel.pcx>;// A 640x480 empty PCX
bmap screen_shot_map2 = <emptypanel2.pcx>;// A 800x600 empty PCX
bmap screen_shot_map3 = <emptypanel3.pcx>;// A 1024x768 empty PCX
bmap screen_shot_map4 = <emptypanel4.pcx>;// A 1280x960 empty PCX

panel respawn_flash
{
   bmap = white_flash; // compass_map as panel background
   pos_X = 0; pos_y = 0;
   layer = 4; // we want the flash in front of the burn image
   flags =  VISIBLE,TRANSPARENT;
}

// copies the screen into a bitmap
function grab_screen() {
  if(video_mode == 6) // 640x480
   {
		bmap_for_screen (screen_shot_map, 1, 0);   
  	}
  if(video_mode == 7) // 800x600
   {
		bmap_for_screen (screen_shot_map2, 1, 0);   
  	}
  if(video_mode == 8) // 1024x768
   {
		bmap_for_screen (screen_shot_map3, 1, 0);   
  	}
  if(video_mode == 9) // 1280x960
   {
		bmap_for_screen (screen_shot_map4, 1, 0);   
  	}
  wait (1);  // wait 1 frame until the bitmap can be saved
}

panel respawn_burn
{
   bmap = screen_shot_map;
   pos_X = 0; pos_y = 0;
   layer = 3; // we want the burn behind the flash
   flags =  VISIBLE,TRANSPARENT;
}

function flash()
{
  if(video_mode == 6) // 640x480
   {
		respawn_burn.bmap = screen_shot_map;  
  	}
  if(video_mode == 7) // 800x600
   {
		respawn_burn.bmap = screen_shot_map2;  
  	}
  if(video_mode == 8) // 1024x768
   {
		respawn_burn.bmap = screen_shot_map3;  
  	}
  if(video_mode == 9) // 1280x960
   {
		respawn_burn.bmap = screen_shot_map4;   
  	}
	respawn_burn.alpha = 100;
	respawn_flash.alpha = 100;
}

starter respawn_panel_control
{
	while(1)
	{
		if(respawn_burn.alpha > 0)
		{
			respawn_burn.alpha -= time*2;
		}
		if(respawn_flash.alpha > 0)
		{
			respawn_flash.alpha -= time*3;
		}
		wait(1);
	}
}

---

Put this at the top of your code, and when you want the magic to happen, just call the function:
Code:

---

 
grab_screen();
flash();
 

---

in your code. Make sure you dont have it in a loop, and you create the images i mentioned in comments.

The bigger the screen size, the longer it takes to capture the screen.. Theirs a small delay for me on 640x480 and 800x600 but after that it gets pretty laggy.