Carrie is an all time clasic horror film and a master of suspense which builds to the destruction of the final act. The image is of Carrie just before the pigs blood gets dumped on her - a moment of innocence and joy,  that is soon ended and triggers her murder spree. The pink background is similar to her prom dress, and having the quote "They're All Gonna Laugh At You", in red, referencs the blood.