I'm trying to find images used in a wall calendar produced by the New
York City Ballet in the mid to late 90s.  The images are of dancers
outside in famous new york settings.  I've had no luck with google
images, so how can I find these images online or elsewhere?

Have you contacted the NYCB directly to ask them for an out-of-print back issue?

The calendar is mentioned here:
http://www.nycballet.com/nycballet/giftshop_welcome.asp
Look under "Gifts and Souveniers"

..."NYCB Gifts & Souvenirs
If you are looking for a memento or simply want a favorite image to
hang on a wall, this is the Shop for you. Here you will find posters,
classic tee shirts and sweatshirts, as well as the ever-popular NYCB
Calendar..."

The CONTACT US page has this contact:

..."Contact Us

If you have any questions or require information about New York City
Ballet or the NYCB website, contact our Director of Online Media at
clanders@nycballet.com.  ..."

Good Luck.