I'm planning my first trip to Tetons and Yellowstone next Sept for a week. I'm wondering to save another flight if it's better to add a few more days and see Glacier or should I do it another year along with International peace park? I do small hikes and photography but no overnight camping etc. Interested in wildlife and scenery
Thank you

I would tack on at least 5 days at the beginning and go to Glacier from Spokane WA instead of SLC. If you rent the car at Spokane, you don't even have to go to SLC.
Your other option is to take the Amtrak Empire Builder overnight from Spokane to Whitefish and rent a car there.

Where are you flying in FROM?

Glacier National Park is a hiker's paradise and I could easily spend 2 weeks there. But if your goal is only shorter hikes and photography/wildlife, I would probably just add extra days on to your current trip. There are lots of short hikes and/or hikes you can shorten if you want to see amazing scenery and wildlife.

Spend one day on the west side of the park, drive the Going to the Sun Road and visit the east side of the park at Many Glacier. I would spend minimum 2 nights at Many Glacier.

The best hike on the east side is Trail of the Cedars/Avalanche Lake.

Along the Going to the Sun Road and Many Glacier area are Hidden Lake Overlook, Highline Trail (this trail you can go out as short or long as you like and will see amazing scenery), St. Mary/Virginia Falls, Redrock Falls, Swiftcurrent Lake Loop. Many Glacier area is your best chance to see grizzlies and moose. We have always seen big horn sheep on the Highline trail.

This is a good reference for trail and wildlife info:

http://www.hikinginglacier.com/
http://www.hikinginglacier.com/glaci...life-hikes.htm

You have picked three of my favorite parks to visit! Enjoy your trip!