Q: What did Cinderella say when her photos did not show up?
A: Someday my prints will come!

Explanation: The phrase would be, “Some day my prince will come.”  Cinderella is waiting for her prince charming to sweep her off her feet.  If she sent in some pictures to be developed she would wait for her prints to be printed, her pictures to be printed on paper.

This joke is funny because the word “prints” and the word “prince” sound the same.  But they have very different meanings