the first image (post opening credits)
the last image (pre closing credits)
first and last bits of regular dialogue if you need another clue
first ~ "And now the window opens, it gently gently opens.Can you guess the movie?
"last ~ "See you later."
The colorful film is [Highlight for the answer] ON A CLEAR DAY YOU CAN SEE FOREVER (1970) starring Barbra Streisand. And yes she's singing in the sky in that final shot.
more first and last puzzles here.