I heard that with memcpy it should be faster, and it seems to be, but the result is not good. This is what I'm doing:
memcpy (screen->pixels, image->pixels, resWidth*resHeight*colorDepth/8); // /8 because the colorDepth is in bits
SDL_BlitSurface(image, NULL, screen, NULL);
The result isn't good. It isn't filling the entire screen, and what it does fill is not correct... Any ideas?