There is actually a way to prepare the background once and then use it, sure, but, since the whole window needs to
completely updated every cycle, it's most likely that just drawing the image directly is more efficient.
Anyway, the 'way' would be to draw to it the background (single image or multiple images/layers). Then draw the render texture to the window (probably using a sprite/quad) each cycle before all your sprites. Note that this
still requires the background to be drawn before the sprites every cycle but allows the construction of a single background from many parts to occur only once. If your background is a single image (as you did actually mention), there's little use for this method
Remember that the window should be
completely updated and refreshed every single cycle/tick/frame. Graphics cards expect this sort of arrangement now. If, however, you are programming for a different system such as SNES, this would probably be impossible to do. If you are programming a SNES-like game on modern hardware, however, you need to follow the 'rules' of modern hardware.