Optimal opening and blitting

SDL Development
1

I am confused about the optimal way to open an image and prepare it for
blitting.

This is my current method:
SDL_Surface *temp, *finished;

temp = LoadImageFromPath(itemPath); //wraps SDL_Image's PNG loader
SDL_SetColorKey(temp, SDL_SRCCOLORKEY | SDL_RLEACCEL,
              temp->format->Rmask | temp->format->Gmask |

temp->format->Bmask | SDL_ALPHA_TRANSPARENT );
finished = SDL_DisplayFormat(temp);
SDL_FreeSurface(temp);

Is this right? Should I call SDL_DisplayFormat() before
SDL_SetColorKey()? What would be the best way to prepare an image to be
blit to the screen (with minimal overhead from per-blit conversion
etc)?

Thank you for your time.